Press 1 pita bread round gently into a medium microwave-safe bowl. Microwave at HIGH 1 1/2 minutes or until crisp. Repeat procedure with remaining pita bread rounds. Set aside.
While pitas cook, bring 1/2 cup water to a boil in a medium saucepan. Remove from heat. Add couscous; cover and let stand 5 minutes or until couscous is tender and liquid is absorbed. Fluff couscous with a fork, and transfer to a medium bowl.
Add garbanzo beans and next 6 ingredients to couscous; toss gently. Spoon couscous mixture evenly into pita bread bowls. Top each serving with 1 tablespoon yogurt.