1. Combine first 10 ingredients in a food processor. Process until finely chopped. Divide mixture into 4 equal portions; shape each portion into a 1/2-inch-thick patty. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add patties to pan; cook 3 minutes on each side or until lightly browned.
2. Combine cucumber, yogurt, juice, and 1/8 teaspoon salt in a small bowl. Line each pita half with 1 lettuce leaf and 2 tomato slices. Place 1 patty in each pita half. Top each patty with about 1 tablespoon cucumber mixture.