Place 1 small head red cabbage in a colander and sprinkle with 1 teaspoon salt. Let it rest for 15 minutes.
I let the cabbage rest while I prepare and cook the fish. Then I make the coleslaw before starting on the tortillas.
In a large mixing bowl, whisk together 3/4 cup plain non-fat Greek yogurt, 1/2 cup mayonnaise, 1 tablespoon honey, 2 teaspoons lime zest, 2 ½ tablespoons lime juice, 2 cloves garlic, and 1/2 teaspoon ground cumin until smooth. Add black pepper to taste.
Shake the cabbage to drain any excess moisture, then transfer it to the bowl of dressing along with 1/2 cup fresh cilantro, 3 green onions, and 1 large jalapeno. Toss to coat. Season with salt and pepper to taste, if needed. Set aside.
Tacos
In a shallow bowl, combine 1/2 cup all-purpose flour, 1 teaspoon ground cumin, 1/2 teaspoon chili powder, and 1/2 teaspoon salt. Dredge the pieces cut from 1.5 pounds halibut fillets in the seasoned flour until each one is fully coated. Set aside on a plate.
Add 1/2 cup avocado oil to a large skillet over medium-high heat. Once the oil is hot, cook the fish in batches for 2 minutes per side, using tongs to gently turn the pieces. Transfer the cooked fish to a paper towel-lined plate and continue until all of the halibut has been cooked.
Place a second skillet over medium heat. Once hot, toast each of the 12 corn tortillas for 30 seconds per side. Transfer to a plate and cover with a kitchen towel to keep warm while you toast the remaining tortillas.
To assemble, arrange a heaping spoonful of cole slaw down the center of a tortilla. Top with 3-4 pieces of fish. Garnish with a squeeze of fresh lime juice and chopped cilantro. Serve immediately.
Notes
There will be extra cole slaw leftover. You can serve some of it as a side dish with the tacos, or make a half-batch.
If you want to save some cole slaw for later, I recommend storing half the veggies and half the dressing in separate containers. Then mix together when you're ready to eat.