1. Rinse the rice in a strainer under cold, running water for 30 sec. Add to a medium pot with 3 cups water and bring to a boil. Reduce to a simmer and cook, covered, for 18 min., or until rice is tender.
2. Meanwhile, heat the vinegar, salt, and sugar in a pot over low heat and stir until the sugar and salt are dissolved.
3. Mix the rice with the dressing in a shallow glass or plastic bowl. (Do not use metal, as it may react with the dressing.) Set sushi rice in the refrigerator for 7 min. Every few minutes, fluff the rice to ensure it cools throughout.
4. Cut the avocado in half lengthwise. Remove the pit, then peel and cut the flesh lengthwise into strips.
5. Wrap the sushi mat in plastic wrap. Set a sheet of nori on top. With wet hands, spread 1 cup of the rice over the nori. Leave a 1-inch strip of nori uncovered on the long side furthest from you. On the side closest to you, spread 1/2 tsp wasabi, add a piece of crab, and place a couple slices of avocado on top. Roll the bamboo mat from the bottom, tightly pressing down after each roll until you reach the end.
6. Dip a sharp knife in hot water and cut the roll into 6 equal pieces. Repeat for 3 more rolls.
Per serving: 486 calories, 6g fat, 1g saturated fat, 0mg cholesterol, 1039mg sodium, 95g carbohydrate, 4g fiber, 5g sugar, 9g protein