1. Prep charcoal grill with medium-hot coals or heat gas grill to medium-high.
2. Using 12-inch-wide heavy-duty aluminum foil, cut 4 pieces 32 inches long; fold each piece in half to make a 16 x 12-inch rectangle. Generously coat foil pieces with nonstick cooking spray.
3. In a large bowl, stir together 2 teaspoons of the oil, 1/4 teaspoon of the salt and 1/4 teaspoon of the pepper. Toss with tomatoes and olives. Evenly place mixture on one half of each foil piece.
4. In the same bowl, combine garlic, lemon zest, remaining 2 teaspoons olive oil, 1/4 teaspoon salt and 1/4 teaspoon pepper, and mix well. Add shrimp; toss to coat completely. Divide shrimp evenly among packets, arranging over tomato mixture.Create a packet:
5. Fold second half of foil over shrimp and vegetables. Tightly seal sides and front edges, leaving space for steam to build. Place packets on grill rack; grill 12 to 15 minutes. Carefully open packets; transfer contents to 4 serving plates. Sprinkle each serving with chopped parsley, and serve with brown rice on the side. (See photo, page 172.)