1. Soak 12 wooden skewers 20 minutes.
2. Whisk together yogurt, 2 tablespoons mint, feta, garlic, lemon juice, and zest. Cover and chill.
3. Mix parsley and next 6 ingredients in a bowl. Form into 12 balls; thread onto skewers. Shape into ovals.
4. Coat grill pan with cooking spray; preheat over medium-high heat. Cook kebabs, turning, 4 minutes for medium.
5. Coat nonstick skillet with cooking spray; heat over medium heat. Cook onion 2 minutes. Stir in peas; cook 3 minutes. Remove from heat; stir in remaining 2 tablespoons mint.
6. Divide vegetables and skewers among 4 plates. Serve with yogurt sauce.