The ancho chile, a dried poblano pepper, is a mild chile. Its flavor is sweet and earthy with hints of dried fruit.
- Combine cilantro, oil, 3 tablespoons lime juice, 1 1/2 tablespoons chile powder and garlic in large zipper closure food storage bag. Add hailbut; seal bag. Marinate in refrigerator 20 minutes to 1 hour. Remove fish from marinade; discard marinade. Season each side of fillet with 1/2 teaspoon kosher salt. Spray grill rack with no-stick cooking spray. Using direct heat cooking method, arrange fish on grill 4-5 inches from medium-hot coals. Grill, uncovered, until fish flakes easily with a fork (about 10 minutes per inch of thickness, measured at its thickest part) turning once. In small bowl, combine avocado, mayonnaise, 1 teaspoon chile powder, 2 teaspoons lime juice and remaining 1/4 teaspoon kosher salt until well mixed.
To Assemble Tacos: Spoon 1/8 of halibut into one taco shell, gently flaking to cover shell evenly. Sprinkle with 1 tablespoon shredded cabbage, a dollop of avocado mixture, 1 tablespoon diced tomato and 1 teaspoon of cheese. Top with a squeeze of fresh lime juice. Repeat with remaining taco shells.