Keto Tuna Sushi Cucumber Boats

Finding a light, healthy lunch that actually fills you up can feel impossible, especially when you’re trying to avoid heavy carbs or bread. Between work deadlines and running around after the kids, it’s tempting to just grab whatever’s quick and easy, even if it leaves you hungry an hour later.

That’s where these tuna sushi cucumber boats come in handy. They give you all the fresh flavors of sushi without the rice, they’re surprisingly filling, and you can make them in about 15 minutes with ingredients you probably already have in your kitchen.

What Kind of Tuna Should I Use?

For the best flavor in your sushi cucumber boats, I’d recommend using good quality oil-packed tuna rather than the water-packed variety. Oil-packed tuna has a richer taste and better texture that works perfectly for this recipe. You can use either chunk light or solid white albacore tuna – both will taste great, though albacore tends to have a milder flavor and firmer texture. If you’re feeling fancy, you could even use jarred Italian tuna, which is often higher quality than canned versions. Just make sure to drain the tuna well before mixing it with the other ingredients, regardless of which type you choose.

Options for Substitutions

This recipe is pretty adaptable, so here are some easy swaps you can make:

• Tuna: While oil-packed tuna gives the best flavor and texture, water-packed works too – just drain it well and maybe add an extra tablespoon of mayo. You could also use canned salmon or even cooked shrimp for a different twist.
• English cucumber: Regular cucumbers work fine, but you’ll need to peel them and scoop out the seeds since they’re not as crisp. Persian cucumbers are another great option if you can find them.
• Rice vinegar: No rice vinegar? Try white wine vinegar or even regular white vinegar, but use a bit less since they’re stronger. Apple cider vinegar works too for a slightly different flavor.
• Wasabi paste: If wasabi is too spicy for you, cut it in half or skip it entirely. You could also substitute with a small amount of horseradish or even a pinch of ground ginger for some kick.
• Nori seaweed: The nori adds that authentic sushi flavor, but if you can’t find it, you can skip it or try sprinkling some everything bagel seasoning for a different but tasty twist.
• Sesame seeds: Either white or black sesame seeds work great, or you can use toasted sesame seeds for extra flavor. In a pinch, chopped green onions make a nice garnish too.

Watch Out for These Mistakes While Cooking

The biggest mistake when making tuna sushi cucumber boats is not draining your tuna properly, which can make your filling watery and cause it to slide right out of the cucumber boats – press the tuna with paper towels or let it sit in a fine mesh strainer for a few minutes before mixing.

Another common error is cutting your cucumber boats too thin or not scooping out enough flesh, leaving no room for the filling and making them prone to breaking – aim for boats that are about ½ inch thick with a good hollow center.

When it comes to the wasabi, start with less than the recipe calls for and taste as you go, since wasabi strength can vary dramatically between brands and your tolerance might be different than expected.

Finally, assemble these boats right before serving rather than letting them sit, as the cucumber will release water over time and make everything soggy.

What to Serve With Tuna Sushi Cucumber Boats?

These cucumber boats make a perfect light lunch on their own, but they’re also great as an appetizer before a bigger meal. I love serving them alongside some edamame with sea salt and maybe a small bowl of miso soup to keep the Japanese theme going. If you want to make it more filling, try pairing them with some steamed rice or a simple seaweed salad from your local Asian grocery store. For drinks, green tea or even a cold sake works beautifully with the fresh, clean flavors of the cucumber and tuna.

Storage Instructions

Refrigerate: These cucumber boats are best enjoyed fresh, but you can store them in the fridge for up to 2 days in an airtight container. The cucumber might release a bit of water over time, so just pat them dry with a paper towel before serving. I like to make the tuna mixture ahead and assemble the boats right before eating for the crispest results.

Make Ahead: You can definitely prep the tuna salad mixture up to 3 days in advance and keep it covered in the refrigerator. The flavors actually get better as they meld together! Just scoop the cucumber boats and fill them when you’re ready to serve for the freshest taste and texture.

Serve Chilled: Since these are meant to be enjoyed cold, there’s no reheating needed. Just pull them straight from the fridge and they’re ready to go. If the cucumber seems a bit soft after storing, a quick rinse under cold water and gentle pat dry can help crisp it back up.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 400-450
• Protein: 22-27 g
• Fat: 30-35 g
• Carbohydrates: 8-12 g

Ingredients

For the tuna salad filling:

• 1 can tuna, oil-packed (7 oz)
• 3 tbsp full-fat mayonnaise
• 2 tbsp minced onion
• 1 tbsp rice vinegar
• 1 1/2 tsp wasabi paste
• 1/4 tsp salt
• 1/4 tsp black pepper
• 1/2 sheet sushi nori (4 by 8 inch)

For assembly and garnish:

• 1 large english cucumber (at least 13 inches long) or six 2-inch sections
• 1 tsp sesame seeds, white or black
• A handful of cherry tomatoes (optional)

Step 1: Mix the Wasabi Tuna Salad

• 1 can tuna, oil-packed (7 oz), drained
• 3 tbsp full-fat mayonnaise
• 2 tbsp minced onion
• 1 tbsp rice vinegar
• 1 1/2 tsp wasabi paste
• 1/4 tsp salt
• 1/4 tsp black pepper

Drain the oil from the can of tuna and place the tuna in a mixing bowl.

Add the mayonnaise, minced onion, rice vinegar, wasabi paste, salt, and black pepper.

Mix thoroughly until the ingredients are well combined into a creamy salad.

Step 2: Prepare and Incorporate Nori

• 1/2 sheet sushi nori (4 by 8 inch)

Cut six 1-inch squares from the half sheet of sushi nori using scissors.

Then, cut each square diagonally in half to make two triangular ‘sails’ and set these aside for garnish.

Cut the remaining nori into long, thin strips and then into small squares.

Stir these small nori squares into the tuna salad from Step 1 for added umami.

Step 3: Prepare the Cucumber Boats

• 1 large English cucumber (at least 13 inches long) or six 2-inch sections

Trim the ends off the English cucumber and cut it into six 2-inch sections.

Slice each section lengthwise in half to create two ‘boats’ per section.

Stand each cucumber boat on end and trim a thin slice of peel from the rounded side so the boat sits flat, cut side up.

Then, using a melon baller or small spoon, scoop out the seeds from each cucumber boat, leaving about a 1/4-inch wall at each end.

I find using a melon baller makes this step quick and neat.

Step 4: Fill and Assemble the Tuna Boats

• prepared cucumber boats from Step 3
• wasabi tuna salad with nori from Step 2
• nori sails from Step 2

Fill each hollowed cucumber boat with about one tablespoon of the wasabi tuna salad (from Step 2), mounding the filling slightly.

Use a butter knife to make a shallow slit in the tuna salad, then insert a nori triangular sail into the slit.

Gently pinch the tuna salad around the base to hold the sail upright.

Arrange the finished tuna boats on a serving platter.

Step 5: Garnish and Serve

• a handful of cherry tomatoes (optional)
• 1 tsp sesame seeds, white or black

If using, cut a handful of cherry tomatoes in half and scatter among the tuna boats.

Sprinkle the sesame seeds over the boats and tomatoes.

Serve immediately for best flavor and texture, or refrigerate the tuna salad and cucumber boats separately and assemble just before serving.

To make the dish even more delicious, I like to use freshly toasted sesame seeds for garnish—they add a wonderful nutty aroma.

Keto Tuna Sushi Cucumber Boats

Delicious Keto Tuna Sushi Cucumber Boats recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 5 minutes mins

Cook Time 12 minutes mins

Total Time 17 minutes mins

Servings 4

Calories 425 kcal

Ingredients

  

For the tuna salad filling:

• 1 can tuna, oil-packed (7 oz)
• 3 tbsp full-fat mayonnaise
• 2 tbsp minced onion
• 1 tbsp rice vinegar
• 1 1/2 tsp wasabi paste
• 1/4 tsp salt
• 1/4 tsp black pepper
• 1/2 sheet sushi nori (4 by 8 inch)

For assembly and garnish:

• 1 large English cucumber (at least 13 inches long) or six 2-inch sections
• 1 tsp sesame seeds, white or black
• a handful of cherry tomatoes (optional)

Instructions

 

• Drain the oil from the can of tuna and place the tuna in a mixing bowl. Add the mayonnaise, minced onion, rice vinegar, wasabi paste, salt, and black pepper. Mix thoroughly until the ingredients are well combined into a creamy salad.
• Cut six 1-inch squares from the half sheet of sushi nori using scissors. Then, cut each square diagonally in half to make two triangular ‘sails’ and set these aside for garnish. Cut the remaining nori into long, thin strips and then into small squares. Stir these small nori squares into the tuna salad from Step 1 for added umami.
• Trim the ends off the English cucumber and cut it into six 2-inch sections. Slice each section lengthwise in half to create two 'boats' per section. Stand each cucumber boat on end and trim a thin slice of peel from the rounded side so the boat sits flat, cut side up. Then, using a melon baller or small spoon, scoop out the seeds from each cucumber boat, leaving about a 1/4-inch wall at each end. I find using a melon baller makes this step quick and neat.
• Fill each hollowed cucumber boat with about one tablespoon of the wasabi tuna salad (from Step 2), mounding the filling slightly. Use a butter knife to make a shallow slit in the tuna salad, then insert a nori triangular sail into the slit. Gently pinch the tuna salad around the base to hold the sail upright. Arrange the finished tuna boats on a serving platter.
• If using, cut a handful of cherry tomatoes in half and scatter among the tuna boats. Sprinkle the sesame seeds over the boats and tomatoes. Serve immediately for best flavor and texture, or refrigerate the tuna salad and cucumber boats separately and assemble just before serving. To make the dish even more delicious, I like to use freshly toasted sesame seeds for garnish—they add a wonderful nutty aroma.