Thaw fish, if frozen. Rinse fish and pat dry with paper towels. Cut fish crosswise into 3/4-inch slices. Place fish in a single layer in a greased shallow baking pan. Combine olive oil, cumin, and garlic powder. Brush over fish. Bake in a 450 degree F oven for 4 to 6 minutes or until fish begins to flake when tested with a fork.
Meanwhile, in a medium bowl stir together mayonnaise and lime juice. Add cabbage; toss to coat. Spoon some of the coleslaw mixture into each taco shell; add fish slices and top with Mango Salsa.
Mango Salsa: In a medium bowl combine 3/4 cup chopped, peeled mango or peach; 1/2 medium red sweet pepper, seeded and finely chopped; 2 tablespoons thinly sliced green onion; 1/2 jalapeño chile pepper, seeded and finely chopped; 1-1/2 teaspoons olive oil; 1/4 teaspoon finely shredded lime peel; 1-1/2 teaspoons lime juice; 1-1/2 teaspoons vinegar; 1/4 teaspoon salt; and 1/8 teaspoon black pepper. Makes 1 cup.