Combine salt, olive oil, lime juice, garlic and hot sauce. Pour over fish in a plastic, glass or ceramic container, cover and refrigerate for 2 hours. Grill fish, bell pepper and onion over ash-white coals until lightly browned. For each wrap, spread a tablespoon of sour cream across tortilla. Layer equal portions of fish, pepper, onion, black beans and avocado in a rectangular mound on the tortilla. Fold the bottom edge over and roll the wrap from one side, leaving one end open.