Cook rice in a rice cooker.
Use freshly cooked rice for Onigiri. Once the rice is cooked, fold up the rice using a spatula to allow excess steam to escape.
Place the rice into a bowl. Add salt, salad oil (and ajinomoto if you want to add more flavors) and mix well.
Check how it tastes like and adjust the amount of salt. (When the rice cools down, it tastes less salty. Please also change the amount of salt depends on the time you eat this Onigiri.)
Divide the rice into 4 portions, put each portion on a plastic wrap. First, make a round shape by wrapping softly. And then shape into triangle. Do not push or press hard when shaping Onigiri. After you finish shaping, remove the plastic wrap first to avoid rice from getting wet by extra moisture.
Once the Onigiri cools down or when all the extra moisture evaporates, wrap with seaweed. To make the seaweed crisp and fresh, put them in a frying pan and warm them up for a few minutes to remove moisture. Place few leaves of green shiso and arrange Onigiri on a plate.
