Preheat oven to 400°F.
In a large heavy skillet cook garlic in oil over moderate heat, stirring, until pale golden. Transfer garlic and 1 tablespoon oil to a food processor. Add chick-peas, 1/4 cup water, and salt and pepper to taste and blend mixture until smooth.
Heat oil remaining in skillet over moderately high heat until hot but not smoking and cook broccoli rabe, turning it with tongs, until wilted. Add remaining 1/4 cup water and pepper flakes and simmer, covered partially, until broccoli rabe is crisp-tender and almost all liquid is evaporated, about 2 minutes.
Spread inside sides of pita with chick-pea purée and top with broccoli rabe and Parmesan.
Arrange pita pizzas on a large baking sheet and bake in middle of oven 10 minutes, or until edges are golden.