Make the Sushi Rice: Wash and rinse the rice with cold water. Add the rice and water to the rice cooker. Cook according to the instruction. (You can also cook it in a regular saucepan on the stovetop)
Once cooked, transfer the rice to a large bowl and let it cool down slightly. When it’s still very warm, stir in the sushi vinegar (or the mixture of rice vinegar, sugar, and salt).
Cut the Salmon: Slice the salmon against the grain, with an angle of 30 to 45 degrees. I recommend cutting it to 3-inch long, 1-inch wide, and 1/4-inch thick pieces. (You’ll need to adjust the angle from time to time to get the proper length and thickness.)
Shape the Rice: Take about 3 tablespoons of rice in your right hand. Squeeze it together until it rolls into a firm oval shape. Try to make the bottom flat with the rounded top. (You can dip your hand in tezu* water to prevent sticking.)
Assemble Salmon Nigiri: Place the salmon slice on the root of your fingers. Then take a pea-sized portion of wasabi, and spread in the middle of the fish.
Place the rolled sushi rice onto the salmon, and bend your fingers to cover both the fish and rice together. Press down the rice using the index finger from the other hand.
Turn the fish and rice and let the salmon slice sit on top of the rice. Serve with optional wasabi, soy sauce, along with pickled ginger.