Prepare the rice: Place the rice in a fine-meshed sieve and rinse well under cold water, rubbing the grains of rice between your fingers, until the water runs clear. Drain well.

Combine the rice and water, and cook in a rice cooker according to the manufacturer’s directions.

If you do not own a rice cooker: Combine the rice and water in a medium saucepan. Bring to a boil, reduce heat to low, and cook covered for 16 to 18 minutes or until the water has been completely absorbed. Remove from heat, fluff the rice, cover with a clean towel and let stand covered for 10 minutes.

While the rice cools slightly, prepare the onigiri filling.

In a medium bowl, combine the albacore tuna, mayonnaise, hot sauce, and rice vinegar until evenly combined. Stir in the scallions.

Set aside a bowl of room temperature water and a small bowl of kosher salt. Once the sushi rice is cool enough to handle, start assembling the onigiri.

Lightly moisten your hands by dipping them in the water bowl. Sprinkle your palms with kosher salt. Grab roughly ½ cup of sushi rice and gently press into an oblong shape.

Add a tablespoon of the tuna filling to the center of the rice and close the rice over the filling.

Gently shape the rice ball into a wide triangular shape. Avoid compressing the rice too hard. Sprinkle the outside with black sesame seeds.

Wrap each onigiri in a nori sheet and place an additional small spoonful of tuna filling on top. Serve immediately.