Stir together tomatoes with their liquid, onions, pine nuts, olive oil, balsamic vinegar, garlic, cumin, allspice, black pepper, salt and ground red pepper in a large bowl; break up tomatoes slightly with a wooden spoon.
Pour tomato mixture into medium-size saucepan. Cook, covered, over medium heat for 10 to 12 minutes or until mixture is slightly thickened.
Meanwhile, bring the 1-1/3 cups water to boiling in a small saucepan. Combine couscous and dried mint in a bowl. Add to boiling water; stir. Cover saucepan; remove from heat. Let stand, covered, 5 minutes. Uncover; fluff with fork. Stir in 1/3 cup of the feta cheese. Cover saucepan again.
Add shrimp to tomato mixture; cover and cook, stirring occasionally, for 2 to 3 minutes or until shrimp are cooked through.
To serve, spoon couscous on large platter; top with shrimp mixture and sprinkle with remaining 1/3 cup feta cheese. Garnish with fresh mint leaves if desired. Makes 6 servings.