How to Make It
In a small bowl, combine the olive oil, garlic, serranos, paprika and 1 teaspoon of pepper. Put the snapper fillets in a large glass dish and rub with the marinade. Cover and refrigerate for at least 30 minutes or up to 4 hours.
In a large bowl, toss the green and red cabbage with the red onion. In a small bowl, mix the yogurt and mayonnaise. Pour over the cabbage, season with salt and pepper and toss. Cover the coleslaw and refrigerate.
In a food processor, puree the avocados with the lime juice. Blend in the sour cream. Scrape the avocado cream into a bowl and season with salt and pepper.
Light a grill. Season the snapper fillets with salt and pepper. Grill the fish over a moderately hot fire for about 3 minutes per side, or until just cooked through. Transfer the fish to a platter, break the fish into large chunks and cover loosely with foil. Wrap 3 stacks of 12 tortillas in foil and place on the grill until heated through, about 5 minutes.
To assemble each taco, spread a dollop of avocado cream on a tortilla. Top with a piece of fish, a large spoonful of coleslaw and some cilantro leaves. Pass the lime wedges, hot sauce and remaining coleslaw at the table.