Combine tomato, cucumber, red onion, cilantro, and lime juice in a small bowl. Season with salt and pepper. Let salsa rest until ready to serve tacos.
Heat grill to medium-high. Cut fish into 12 equal portions. Season with salt and pepper.
Oil grill grates and transfer fish to grill. Cook until opaque and flakey, about 4 minutes per side. Transfer cooked fish to a plate. Place tortillas on grill and cook, turning, until nicely toasted.
To assemble, place shredded lettuce, avocado, and salsa on a tortilla. Add 2 fish filets per tortilla and top with Citrus Crema. Finish with pickled cabbage. Garnish with lime segment and cilantro and eat right away or tortilla will become soggy.
For Pickled Red Cabbage: Combine 3 cups shredded red cabbage, 1 cup red wine vinegar, ½ cup water, and 1 tablespoon sugar in a saucepan over medium-high heat. Bring to a boil, stirring occasionally. Turn off heat and let cabbage mixture sit for 5–7 minutes. Cabbage should be slightly soft, but still crunchy.
For Citrus Crema: Combine ½ cup sour cream, chili powder to taste, and zest from both a lime and an orange in a small bowl.
Recipe courtesy of Chef Doug Vogel, Maggie's Seafood