Thaw fish, if frozen. Rinse fish; pat dry with paper towels. If necessary, cut fish into 4 serving-size pieces. For marinade, in a blender container combine chipotle peppers, adobo sauce, sweet pepper, lime juice, oregano, and garlic. Cover and blend until pureed. Transfer half of the marinade to a shallow dish; set aside remaining marinade.
Add fish steaks to dish, spooning some of the marinade over fish. Cover and marinate at room temperature for 30 minutes.
Drain fish, discarding marinade. Sprinkle fish with salt. Grill fish on the greased rack of an uncovered grill directly over medium coals for 8 to 12 minutes or until fish flakes easily when tested with a fork, turning once halfway through grilling. Heat reserved marinade and serve as sauce with fish. Makes 4 servings.