Place fish in a shallow baking dish; sprinkle with 2 tablespoons lime juice and 2 minced garlic cloves. Sprinkle with 1/2 teaspoon cumin, 1/4 teaspoon salt, and 1/4 teaspoon black pepper. Set aside.
Combine diced mango, next 4 ingredients, remaining 1/4 cup lime juice, and remaining 1/4 teaspoon each of cumin, salt, and black pepper in a large bowl; toss well, and set aside.
Place fish on grill rack coated with cooking spray. Grill 7 to 8 minutes on each side or until fish flakes easily when tested with a fork. Flake fish into bite-sized pieces with fork.
Warm tortillas according to package directions.
Top each tortilla with about 1/4 cup fish, 2 tablespoons mango salsa, and 2 tablespoons slaw.