How to Make It
Place oven rack in upper third position and heat broiler to low. Line a baking sheet with aluminum foil. Brush pita tops with oil and arrange on baking sheet. Broil, turning once, until lightly toasted, about 2 minutes per side.
Divide hummus among pitas, spreading evenly, and top with chickpeas, olives, onion, cheese, and crushed red pepper, if using. Return to oven and broil until cheese is softened, about 6 minutes (watch carefully, as broiler strength varies).
Serve pita pizzas warm, topped with mint.