Place pita breads on a baking sheet and bake in preheated oven until golden and crispy, about 5 minutes. Allow to cool, then tear into bite-sized pieces.
In a large bowl, mix together lettuce, tomatoes, green onions, cucumber, green olives, radishes, green peppers, and toasted pita. Season with mint, sumac, and salt; toss until evenly combined. Pour in lemon juice and olive oil; stir to combine.
