Combine the cabbage, tomatoes, green onions, and cilantro in a large bowl and toss to combine. Add the lime juice and 1/4 teaspoon. sea salt and toss well to combine. Set aside.
Combine the chili powder, cumin, and remaining 1/4 teaspoon. salt in a small bowl. Heat the remaining 2 tablespoon. olive oil in a large nonstick skillet over medium-high heat. Season the fish with the seasoning.
Add the seasoned fish to pan and cook 3-4 minutes on each side, or until it flakes easily when tested with a fork.
Remove from heat, and slice into bite-sized pieces.
Lay a tortilla flat and fill with the fish, followed by the cabbage mixture. Serve hot.