When you want a quick, protein-packed Japanese comfort food, Spicy Tuna Onigiri is an absolute staple. Seasoned sushi rice is stuffed with a savory, spicy canned tuna filling, shaped into neat handheld triangles, and wrapped with a crisp strip of nori (seaweed) for effortless holding.
The secret to perfectly shaped onigiri that hold together without sticking to your hands is Using Warm Short-Grain Rice and Salted Water. Long-grain rice (like basmati or jasmine) lacks the starch needed to bind the triangle together. Warm, short-grain sushi rice clings together naturally, while dipping your hands in lightly salted water prevents the rice from sticking to your palms while adding a subtle seasoned finish to the outer layer.
Why You’ll Love These Rice Balls
- Incredible 15-Minute Prep: Uses simple pantry staples like canned tuna, mayo, and Sriracha.
- Handheld & Portable: Perfect for quick lunches, snacks, or on-the-go meal prep.
- Spicy & Savory filling: Rich canned tuna elevated with creamy Japanese mayo, Sriracha, and sesame oil.
- Fun to Make: Easy to shape by hand or using a inexpensive plastic onigiri mold.
Key Ingredients Overview
- Short-Grain Sushi Rice: Warm, cooked sushi rice (or short-grain white rice) provides the ideal sticky texture.
- Canned Tuna: Drained thoroughly to keep the filling from watering down the rice.
- Kewpie Mayo & Sriracha: Japanese mayonnaise adds rich, tangy creaminess, while Sriracha provides the signature heat kick.
- Nori (Seaweed Sheets): Cut into thin strips to wrap around the bottom for grip and crisp texture.
Step-by-Step Instructions
1.The Spicy Tuna Mix:2 min.
Drain 1 can (150g / 5 oz) of tuna completely. In a small bowl, flake the tuna with a fork and mix with 2 tablespoons Japanese Kewpie mayo (or regular mayo), 1 to 2 teaspoons Sriracha, ½ teaspoon toasted sesame oil, and 1 finely sliced green onion until smooth.
2.The Salt-Water Hand Prep:2 min.
Fill a small bowl with water and add ½ teaspoon of salt. Wet both hands thoroughly in the salted water and rub a pinch of dry salt over your palms. This keeps the warm short-grain rice from sticking to your skin while seasoning the outside.
3.The Filling & Triangle Shape:5 min.
Scoop about ⅓ cup of warm cooked sushi rice into your palm and press a small indentation in the center. Spoon 1 tablespoon of the spicy tuna mixture into the center, then place another 2 tablespoons of rice over top to enclose the filling. Cup your hands into a ‘C’ shape and gently press into a compact triangle, rotating as you press so it holds its form.
4.The Nori Wrap & Serve:1 min.
Wrap a strip of nori seaweed around the bottom of the triangle. Sprinkle the top edges with Furikake seasoning or toasted sesame seeds, and serve immediately while the seaweed is crisp!
Expert Tips for Success
- Use Warm Rice: Cold, leftover rice loses its stickiness and will crumble when shaped. If using pre-cooked rice, microwave it until warm before shaping!
- Drizzle or Mix in Furikake: For extra savory umami, mix 1 tablespoon of Furikake (Japanese rice seasoning) directly into the warm rice before shaping.
- Keep Nori Dry Until Serving: If packing onigiri for lunch, keep the nori strips wrapped separately in plastic and apply them right before eating so they stay crispy rather than soft.
The Recipe Card
- Prep Time: 10 mins
- Cook Time: 0 mins (using pre-cooked rice)
- Total Time: 10 mins
- Yield: 3 to 4 Onigiri
Ingredients:
- The Rice Outer: 2 cups Cooked Short-Grain Sushi Rice (warm), Furikake seasoning or toasted sesame seeds (for garnish).
- The Spicy Tuna Filling: 1 can (150g / 5 oz) Canned Tuna (drained), 2 tbsp Kewpie Mayonnaise, 1–2 tsp Sriracha, ½ tsp Toasted Sesame Oil, 1 Green Onion (finely sliced).
- The Wrap & Assembly: 1 sheet Nori Seaweed (cut into 1-inch strips), Bowl of salted water.
Instructions:
Mix drained canned tuna with Kewpie mayo, Sriracha, sesame oil, and sliced green onion. Wet hands in salted water. Cup warm sushi rice in your hand, make a small well, insert 1 tbsp spicy tuna filling, and cover with more rice. Gently compress and shape into a compact triangle. Wrap a nori strip around the base, garnish with sesame seeds, and serve.
