In a medium skillet, heat 1 tablespoon oil over medium heat. Add the jalapeno, chopped red onion and garlic and cook for 4 minutes. In a small bowl, mash the black beans with the cumin and season with salt and pepper; cover.
In a large bowl, combine 2 tablespoons oil with the honey, hot sauce and lime juice; season with salt and pepper. Add the sliced onion, cabbage and cilantro; toss.
Preheat a grill or grill pan to medium. Coat the fish with the remaining 1 tablespoon oil and the lime peel. Cover and grill the fish, turning once, for 8 minutes.
Warm the taco shells and tortillas on the grill. Spread a few spoonfuls of mashed beans (stir 1 to 2 tablespoons hot water into the beans if too thick) on the outside of the tacos, and wrap a tortilla around each one, pressing to adhere.
Flake half a piece of fish into each taco shell and top with some cabbage slaw. Serve 2 tacos per person, with the creme fraiche and extra slaw on the side.