Grilled Fish Tacos are customizable on corn or flour tortillas. We recommend some salsa and avocado.
Preheat gas or charcoal grill.
Place fish fillets on a plate; rub each fillet on both sides with the oil. In a small bowl combine chili powder, cumin, salt, and pepper; rub onto fillets on both sides. Stack tortillas, if using, and wrap in foil. For chipotle cream, in another small bowl stir together sour cream and chopped chipotle pepper; set aside.
For a charcoal grill, place fish and tortilla stack on the greased rack of an uncovered grill directly over medium coals until fish just flakes easily when tested with a fork and tortillas are heated through, turning fish and tortilla stack once. (Allow 4 to 6 minutes per 1/2-inch thickness of fish). (For a gas grill, preheat grill. Reduce heat to medium. Place fish and tortilla stack on greased grill rack over heat. Cover and grill as above.)
Top tostada shells or fill warm tortillas with lettuce, fish, and avocado slices. Serve with fresh salsa, chipotle cream, lime wedges, and cilantro, if desired.
Prepare as above, except substitute 6 tostada shells for the tortillas and omit stacking and grilling.