Step 1: Prepare the Cilantro Lime Slaw: In a medium bowl, combine shredded cabbage, carrots, and fresh cilantro. In a small separate bowl, whisk together mayonnaise, lime juice, sugar, salt, and pepper until smooth. Pour the dressing over the slaw mixture and toss to coat evenly. Cover and refrigerate while you prepare the fish.
Step 2: Prepare the Fish: Pat the fish strips very dry with paper towels. In a shallow dish, whisk together flour, cornstarch, chili powder, smoked paprika, garlic powder, onion powder, cayenne pepper (if using), salt, and black pepper. Pour buttermilk into another shallow dish.
Step 3: Bread the Fish: Dip each fish strip into the buttermilk, letting any excess drip off. Then dredge the fish in the seasoned flour mixture, pressing gently to ensure it's fully coated. Place the breaded fish on a wire rack while you prepare the remaining pieces.
Step 4: Fry the Fish: Heat about 1 inch of vegetable oil in a large skillet or Dutch oven over medium-high heat until it reaches 350-375°F (175-190°C). Carefully add a few fish strips to the hot oil, ensuring not to overcrowd the pan. Fry for 2-3 minutes per side, or until golden brown and cooked through. Remove the fish and place on a clean wire rack set over paper towels to drain excess oil.
Step 5: Warm the Tortillas: While the fish is still warm, warm the tortillas in a dry skillet over medium heat for about 15-30 seconds per side, or until pliable. Alternatively, wrap them in a damp paper towel and microwave for 30-60 seconds.
Step 6: Assemble Tacos: Assemble the tacos by placing a few pieces of crispy fish into each warm tortilla, topping with a generous amount of cilantro lime slaw. Serve immediately with extra lime wedges and your favorite hot sauce, if desired.