Prepare a bowl of cold water to wet your hands. (This will prevent the rice from sticking to your fingers)For sushi rice:Dissolve the sugar in the rice vinegar.In a fine mesh strainer, rinse the rice with running water until the water is clear.In a saucepan, weigh the rice and add 1.5 times its volume in water.Bring to a boil and cook for 15 minutes over low heat, covered.Let the rice cool.Pour the sugar-vinegar mixture over the rice and mix with a bamboo spatula. Lay a bamboo mat or a plastic food wrap on a work surface.Place a thin, even layer of rice over the entire surface.Cut a sheet of nori.Place a strip of snow crab in the center of the rice.Roll everything up, closing the roll.Sprinkle with sesame seeds. Refrigerate until serving.