- Add sushi rice to a medium bowl and rinse under water 3-4 times, until water runs mostly clear. Transfer to a saucepan and add 3 cups of water. Heat over medium-low heat. Once simmering, cover and cook until tender, about 20 minutes. Stir together rice vinegar, sugar and salt in a small bowl and pour over rice. Gently fold vinegar mixture into rice. Once rice has cooled to room temperature, place in a shallow bowl and refrigerate for 1 hour to chill.
- To make sushi, place 1 sheet of nori seaweed on a bamboo sushi mat. Spread enough rice on seaweed to cover, leaving 1/2 inch around the edges. Gently pat rice on seaweed with a wooden rice paddle or clean fingertips. Arrange a few strips of tuna, cucumber, avocado and cilantro on rice in a row just below the center parallel to you. Use the bamboo mat to firmly roll into a log.
- Using a sharp knife, slice sushi into 1-inch pieces. Repeat with remaining ingredients. Sprinkle sushi with black sesame seeds and serve with less sodium soy sauce for dipping.