Wash the rice well changing two or three times the water to eliminate the starch.
Place the rice in a pot with a thick bottom and cover it with water, about two fingers above the edge of the rice. Put on medium heat until it starts to boil. At this time, lower the fire and cover the pot to prevent steam from escaping. Let it cook for about 10 minutes and put out the fire. Let the rice rest for 10 additional minutes, without removing the lid.
Cut the salmon into thin slices.
Cut the nori seaweed into thin strips.
In a bowl, mix the mirin with the sugar and set aside.
Once the 10 minutes of rest of the rice have passed, move with a wooden spoon and mix well with the mirin previously prepared with the sugar. Let stand again, until the rice completely consumes the mirin.
Assemble the nigiri making rice truffles of the size of your preference. Place a sheet of salmon and, finally, a strip of nori seaweed.
Serve with soy sauce and a little wasabi.