Heat oven to 425°F. In food processor bowl with metal blade or blender container, combine beans, garlic, milk and lemon juice; cover and process until smooth.
Spread about 3 tablespoons mixture onto each pita bread. Place on ungreased cookie sheets. Top each with tomato, cheese, olives and parsley.
Bake at 425°F. for 5 minutes or until pizzas are thoroughly heated and cheese is melted.