4 cups rice
3-1/2 cups water
2-3 Haas avocados
1/4 pound crab stick (available in Japanese markets and some grocery stores)
1 cup rice vinegar
1/2 cup sugar
1/2 cup salt
1/4 pound flying fish roe (optional, found in Japanese markets)
20 large sheets of nori (seaweed), cut in quarters (available in Japanese markets)
Tube of wasabi (horseradish paste, available in Japanese markets)
Rinse the rice several times until the water is clear. For best results, cook it in a rice cooker. Almost all rice cookers automatically turn off when the rice is ready. When the cooker is turned off, leave it for 15 minutes to steam rice. If not using a rice cooker, steam rice according to directions on package.
While the rice is cooking, prepare cucumber, avocado, and crab stick. Peel cucumbers and cut them into three 3-inch-long sections. Cut away and discard the seed core, and julienne. Cut each avocado lengthwise, discard pit, and cut into 12 wedges.
Mix the rice vinegar, sugar, and salt in a large bowl, and then add the cooked rice, mixing it with a flat wooden spoon to keep it from becoming sticky. Japanese cooks also use a hand-held fan to cool the rice (when rice is hot, you cannot hold it) and to spread the vinegar flavor throughout the rice.
Spread 1/4 cup of seasoned rice onto a quarter sheet of seaweed. Add some of the cucumber and the crab stick with avocado. Add flying fish roe if you like. Roll into a cone shape. Dip sushi roll into soy sauce. Those more adventurous may wish to add a small amount of wasabi or horseradish. (Be careful, though, as wasabi is extremely hot.)
For variety, 1-1/2 pounds raw tuna could be added with the cucumber instead of crab stick with avocado to make tekka maki, another type of sushi roll. Slice the tuna into 3-inch-by-1/2-inch strips.