Sushi Rice: place rice in bowl, and rinse with water. Repeat until water is clear. Place rice and 2 1/2 cup water into medium saucepan. Bring to boil, uncovered. Turn heat to low, cover and simmer for additional 15 minutes, or until water has been absorbed. Remove from heat, and let stand for 10 minutes. Combine rice vinegar and salt, and heat in microwave for 30 seconds. Fold vinegar mixture into rice, making sure to coat each grain. Cool at room temperature before making sushi.
Sushi: gently toss avocado in lemon juice to prevent browning. Cover bamboo sushi mat with plastic wrap. Have small bowl of water available. Wet fingers with water, and spread approximately 1/2 cup rice evenly onto nor. Sprinkle rice with sesame seeds. Turn nori rice side down, and place cucumber, avocado and crab sticks in center of sheet. Roll nori evenly, holding crab, cucumber and avocado in place while rolling. Cover with damp cloth or towel and continue with other rolls. Cut each roll into 6-8 pieces, and serve with soy sauce, ginger and wasabi.