Try This Technique:
1. Spread cooked rice in shallow pan. (Good varieties for sushi include Koshi-Hikari from Japan and Kukuho Rose, Silver Pearl, and Tamanishiki, all from California.) Drizzle vinegar mixture over rice. Using a spatula, pull rice toward you, folding it over on itself while being careful not to cut rice grains. Repeat folding process until rice absorbs vinegar mixture.
2. Place seaweed sheet on bamboo mat lined with plastic wrap, or on other flexible material, such as pastry cloth lined with plastic wrap. With moistened hands, spread about 1/2 cup prepared rice evenly over one side of each seaweed sheet, stopping 1 inch short of longer edge.
3. Place cucumber and salmon strips on top of rice. Use finger to dot rice with small amount of wasabi alongside salmon and cucumber strips. With finger, spread wasabi on rice to make thin line.
4. Starting with rice-covered edge, roll up each sheet jelly-roll style. Take care to roll sushi evenly. Moisten seaweed edge with water; press lightly to seal.
5. To cut sushi roll, dip sharp, thin-bladed knife into hot water. Using sawing (back-and-forth) motion and very light pressure, slice each sushi roll crosswise into eight or more pieces. For easier cutting, frequently dip knife blade into hot water.