1. To prepare salsa, combine first 3 ingredients in a bowl. Cover and refrigerate until ready to serve.
2. To prepare Lime Crema, place mayonnaise and next 3 ingredients (through avocado) in a food processor; process until smooth. Cover and refrigerate up to 2 days.
3. To prepare tacos, preheat grill to medium-high heat. Sprinkle fish with salt and pepper. Place fish on grill rack coated with cooking spray; cook 5 minutes on each side or until fish flakes easily when tested with a fork. Remove from grill; break into chunks with a fork.
4. While fish cooks, warm tortillas according to package directions.
5. Spoon 3 ounces fish, 1/4 cup salsa, 1 1/2 tablespoons crema, and 1/4 cup cabbage onto each tortilla; fold in half.