1. Combine first 4 ingredients and 1/4 teaspoon salt in a food processor; process until ground. Divide mixture into 8 equal portions; shape each into a 1/2-inch-thick patty. Heat a large skillet over medium-high heat. Add oil to pan. Add patties to pan; cook 4 minutes on each side.
2. Combine yogurt and next 4 ingredients; stir in 1/4 teaspoon salt. Place 1 lettuce leaf on each of 4 plates. Top with tomato slices; sprinkle with black pepper. Divide cheese evenly among servings. Arrange 2 patties on top of tomato mixture; top each serving with about 2 tablespoons yogurt mixture. Serve with pita wedges.