Cook the brown sushi rice: Rinse the rice and cook it with 1 1/2 cups of water. Bring to a boil, reduce heat, and simmer for 30-35 minutes.
Season the rice: Mix rice vinegar and coconut sugar, then fold into the cooked rice. Let cool.
Prepare the salmon: Slice sushi-grade fresh salmon into thin pieces.
Shape the rice: Mold about 1 tablespoon of rice into an oval shape with wet hands.
Assemble the nigiri: Top each rice mound with a slice of salmon. Optionally, add wasabi paste between the rice and salmon.
Serve: Garnish with sesame seeds and serve with coconut aminos or soy sauce.