in small bowl combine sour cream, mint, pepper and garlic; mix well. Drain chicken; discard marinade. Heat margarine in large skillet over medium-high heat until hot. Add chicken and onion; cook and stir 6 to 8 minutes or until chicken is no longer pink. Spread sour cream mixture over partially baked crust, including edges. Top with Monterey Jack cheese. Using slotted spoon, place chicken mixture evenly over cheese. Top with tomato slices, cucumber and feta cheese. Bake for 10 to 15 minutes or until edges of crust are deep golden brown and Monterey Jack cheese is melted. Garnish with fresh mint leaves, if desired.