MAKE THE SUSHI RICE
Rinse the sushi rice for a minute or two until the water runs clear. If you have time, soak it in water for 15 minutes prior to rinsing.
Add 3 cups of water to a pot over high heat and bring to a boil. Add the salt and rice and once boiling, lower the heat and cover to simmer for 20 minutes. After, turn off the heat but leave covered for 10 more minutes. Then fluff it up.
In a small bowl, add the rice vinegar, granulated sugar, and sesame oil. Microwave for 30 seconds or quickly warm it up in a pot just so the sugar dissolves.
Pour this over the rice and mix so that each grain of rice is coated evenly. It should be very sticky! Set aside.
MAKE THE SALMON MIXTURE
In a bowl, mash the salmon with a fork and add the mayonnaise, sriracha, soy sauce, sesame oil, lime juice, and sliced green onions. Combine until everything is evenly distributed.
ASSEMBLY
Using hands dipped in water, shape about 1/4 cup of rice into a small triangle on a piece of saran wrap.
Add about 2 tablespoons of salmon filling to the center. Cover with rice on top in the shape of a triangle. You can also add thinly sliced avocado inside. Wrap a piece of nori along the bottom.
Wrap each onigiri with tightly with plastic wrap, preserving the triangle shape. Repeat with the rest of the rice and salmon.
OPTIONAL STEP: To make this "yaki" style (which means grilled in Japanese), add a splash of oil to a pan. Brush each onigiri with Japanese BBQ sauce and add onigiri to the pan and fry on each side for 3 minutes until crispy and golden and BBQ sauce has caramelized.
Enjoy with spicy mayo (sriracha & mayo + optional: rice vinegar) or chili oil and more Japanese BBQ sauce!