Add the sushi rice to a fine mesh colander and rinse until the water becomes clear. Place the sushi rice in a small pot and add the water. Bring the water to a boil, then reduce the heat to low, cover the pot and cook the rice for 20 minutes.
While the rice is cooking, cube up the ahi tuna into bite-sized pieces.
In a small bowl, stir together the tamari, sesame oil and rice vinegar. Then add the ahi tuna and gently stir until all of the pieces are coated. Add the green onion and stir again.
When the rice is fully cooked, add a few spoonfuls of rice to a bowl. Top that with a few spoonfuls of ahi tuna, several slices of cucumber and a some diced avocado. Garnish with microgreens and a sprinkle of white and black sesame seeds.
