Cut each slice of bread into quartets. Place the squares on a baking sheet and toast in moderate oven (325°) for 15 minutes or until lightly browned and very crisp. Cool. Blend mayonnaise with chopped watercress and spread on cooled toast. Top each piece of toast with a piece of bacon and a cherry tomato half. *If lettuce is used, spread toast with plain mayonnaise and cover with a small piece of lettuce before topping with the bacon and tomato. app127