Step 1
Combine the cabbage and red onion with 1 teaspoon salt in a colander, set in a bowl and let stand 10 minutes to soften. Pat the cabbage very dry and combine with the apple, jalapeño, lime juice, 1 tablespoon of the oil and the cilantro. Season with salt and pepper to taste and set aside.
Step 2
Sprinkle fish with salt, pepper, Tajin and cumin. Heat half the remaining oil in a large nonstick skillet or well-seasoned cast iron skillet over high heat. When the oil is almost smoking add half the fish and cook 2 minutes. Gently turn and remove from the heat. Cook another 30 seconds to 1 minute. Transfer to a platter and keep warm. Wipe out the skillet and cook the second batch of fish the same way.
Step 3
Build the tacos: On a warm tortilla, place slaw, then cooked fish. Top with cheese and additional Tajin, if desired.
