Combine the chickpeas, lemon juice, tahini paste, and garlic in a food processor fitted with a metal blade. Process until smooth. With the machine running, slowly add the olive oil in a steady stream. Season with salt and pepper. Spoon the humus in the center of a large platter and drizzle with olive oil. Arrange the black olives and fresh pita bread around the hummus.
Yield: about 2 cups