Grilled Lemon Shrimp and Vegetables

Preheat outdoor grill or broiler until hot. In a 13-by-9-by-2 inch glass dish, place shrimp, mushrooms, zucchini, and red onion. In a small bowl, combine olive oil, lemon juice, garlic, oregano, salt and black pepper. Pour over vegetables; toss until well coated. Let stand for 30 minutes. Place vegetables and shrimp on a vegetable grilling rack or a rack in a broiler pan. Grill or broil no more than six inches from heat source until vegetables and shrimp are just cooked, about 8 minutes, stirring often and brushing occasionally with remaining marinade. Serve on pitas with cucumber yogurt sauce.

FOR THE CUCUMBER YOGURT SAUCE:
In a small bowl, combine yogurt ingredients together.