1. Preheat oven to 400 degrees, spray a small rimmed baking sheet with cooking spray.
2. Place bread squares on the baking sheet and spray lightly with cooking spray.
3. Bake for 5 minutes, or until lightly golden brown.
4. Remove and cool.Crisp bacon in a frying pan over medium-high heat, remove to a paper towel lined plate and cool.
5. Spread a small amount of mayonnaise on each bread slice. Top with 3 or 4 pieces of lettuce, then a slice of bacon. Skewer the tomato half with a long toothpick and stick into the bacon, lettuce and bread. Repeat with remaining ingredients.
6. Serve immediately.