Onigiri (tuna Mayo) Recipe

Rinse and soak

Place 2 cups short-grain rice in a fine-mesh sieve and rinse under cold running water, swirling with your hand, until the water runs clear (about 2–3 minutes). Drain. Transfer rinsed rice to a rice cooker or heavy pot and add 2.25 cups water. Let rice soak 30 minutes at room temperature (optional but recommended for evenly cooked grains).

Cook rice

If using a rice cooker, cook according to manufacturer's instructions. If using a pot: cover and bring to a boil over medium-high heat, then reduce heat to low and simmer covered 12–15 minutes until water is absorbed. Remove from heat and let sit, covered, 10 minutes to steam.

Season rice

While rice cooks, combine 2 tbs rice vinegar, 1 tsp sugar and 3/4 tsp salt in a small bowl and stir until dissolved. Transfer hot cooked rice to a large wide bowl (a wooden hangiri or large shallow bowl is ideal) and gently fold in the vinegar mixture with a rice paddle or spatula using cutting-and-fan motions to cool rice to slightly warm (do not mash). Spread the rice to help it cool faster; cover with a damp towel until assembly.

Drain 1 can of tuna thoroughly, then flake with a fork into a mixing bowl. Add 3 tbs mayonnaise, 1/2 tsp soy sauce, 1/4 tsp toasted sesame oil, 1 tbs finely sliced green onion, 1/8 tsp salt, and 1/8 tsp black pepper. Mix until well combined and tastes balanced; adjust mayo or soy sauce to preference. Refrigerate briefly if rice is still warm so filling is cool for handling (filling should be at most slightly warm).

Prepare salted water: dissolve a pinch of salt in 1/4 cup water and keep in a small bowl. Keep a small bowl of cold water nearby to wet hands if rice sticks excessively.

Forming onigiri (triangle method)

Wet your hands with the salted water and shake off excess. Scoop about 3/4 cup of seasoned rice into your palm, gently flatten into a small disk, and place about 1 to 1.5 tbs of the tuna mayo mixture in the center. Fold rice over the filling to enclose it, then cup both hands and press gently into a compact triangle shape (or ball) using firm but gentle pressure — do not over-compress; the rice should hold together. If rice sticks, re-wet hands lightly.

Wrap with nori

Wrap a strip of nori around the base or middle of each onigiri, shiny side out. If you prefer crisp nori, wrap just before eating. Optionally sprinkle toasted sesame seeds on the exposed rice or press seeds lightly into the seam.

Repeat to make 4 onigiri using remaining rice and filling. Taste one and adjust remaining fillings if desired. Serve immediately or wrap individually in plastic wrap and store in the refrigerator up to 24 hours (nori may become soft). Reheat gently in a microwave for 20–30 seconds if desired.