1. Place chopped avocado in a bowl; add scallion and toss gently.
2. Place chopped tomatoes in another bowl along with basil, salt and pepper.
3. Place crab meat in a bowl; gently toss with lemon juice, salt and pepper.
4. Mix together Soy Wasabi Dressing ingredients in a small bowl. Add two tablespoons dressing to chopped avocado.
5. Line an 8-ounce ramekin with plastic wrap. Spoon a fourth of the crabmeat into ramekin and press down with a spoon. Add a fourth of the chopped avocado on top and press down with a spoon. Invert ramekin onto a serving plate by tapping ramekin on plate.
6. Spoon some tomato basil mixture on top of crab and avocado tower. Repeat three more times with remaining crabmeat, avocado and tomato mixture.
7. Drizzle a little more of the Soy Wasabi Dressing on top of the appetizer. Serve as individual appetizer portions or with tortilla chips for a more casual appetizer.