To prepare the salsa, combine the first 6 ingredients in a bowl. Cover and chill.
To prepare tacos, place a large nonstick skillet coated with cooking spray over medium-high heat until hot. Add bell pepper, onion, and garlic; sauté 2 minutes. Add shrimp, tomato, cumin, and chili powder; sauté 3 minutes or until shrimp are done. Stir in cilantro. Spoon 1/2 cup shrimp mixture over one half of each tortilla, and top with about 3 tablespoons cheese and 2 tablespoons salsa; fold tortillas in half.