6 cups prepared sushi rice (<a href="http://cooking.nytimes.com/recipes/10754-sushi-rice">see recipe</a>)
2 Hass avocados in 1/2-inch strips
Salt
1 pound cucumber, carrot or daikon, or a combination, cut into matchsticks
2 sheets nori (7 by 8 inches), cut into confetti
2 pounds fillets of fresh salmon, tuna, yellowtail, fluke or striped bass, in slices 3 inches by 1 inch by 1/4 inch thick
1 bunch scallions, cut in thin rings halfway up the green tops
2 teaspoons sesame seeds