To Complete the Zushi Bowl: Place a cup of rice, cooled to just above room temperature, in the bottom of each of 6 bowls. Add a layer of the avocado slices, distributing evenly in any pattern you choose. Sprinkle a pinch or two of salt over each bowl. Add the raw matchstick vegetables in an even, randomly arranged layer, and sprinkle on the nori confetti. Add the fish on top, arranging as you wish, perhaps in twists or rolls. Scatter scallions and sesame seeds on top. Serve with condiments like soy sauce, wasabi, pickled ginger and rice vinegar, so diners can season and toss sushi with chopsticks or spoons.
To Make Sushi Rice: In a fine strainer, rinse the rice with cold running water, until water runs clear. Pour rice into pot with 2 cups cold water; let sit 30 minutes.
Bring rice to a boil over medium-high heat; immediately turn heat to low and cover. Cook 10 minutes, remove from heat and let sit, covered, 15 minutes. In a small saucepan, dissolve the sugar and salt in the rice vinegar over a low flame. Pour evenly over rice and fold gently with a wooden spoon to mix. Leave rice in front of a fan, or fan with a piece of cardboard for 15 minutes or until rice is just above room temperature. Makes 6 cups.