1. To make hard-boiled eggs, cook the eggs for about 10 minutes in a saucepan of simmering water to cover. Drain eggs from water, cool under cold running water, and peel.
2. Mash avocado, mayonnaise, and lemon juice together in a medium bowl. Stir in the eggs, celery, and chives. Season with salt and pepper, to taste.
3. Toast slices of Wonder® 100% Whole Wheat bread until preference. Spread 4 slices of bread with 1/4 of the avocado egg salad and place a leaf of lettuce on top. Top each sandwich with another slice of toast and serve.