Wash the rice in a mesh strainer under cold running water, gently rubbing the grains together until the water runs clear (about 3-4 rinses).

Combine the washed rice and 4½ cups water in a medium saucepan. Bring to a boil over high heat, stirring occasionally. Once boiling, reduce heat to low, cover with a tight-fitting lid, and simmer until all water is absorbed, about 15-20 minutes.

Remove from heat and let the rice rest, covered, for another 15 minutes to finish steaming. Then, transfer to a large bowl and allow to cool until just warm enough to handle.

Fill a small bowl with water and dissolve 1 teaspoon of salt in it. Have your chosen fillings ready in separate small bowls.

Wet your hands with the salt water solution. Scoop about ½ cup of warm rice into your palm. Make an indentation in the center and add 1-2 teaspoons of your chosen filling. Fold the rice over the filling and shape into a triangle or ball by gently pressing with both hands.

If using nori, wrap a strip around the base of the onigiri.

Optionally roll the shaped onigiri in sesame seeds, furikake, or other desired toppings for extra flavor.