Heat a large ovenproof skillet over medium heat. Add oil; swirl to coat. Add onion; sauté 5 minutes or until tender. Stir in tomato, wine, 1 teaspoon oregano, vinegar, 1/8 teaspoon salt, black pepper, and crushed red pepper; bring to a simmer. Cook 3 minutes, stirring occasionally. Sprinkle fish evenly with remaining 1/4 teaspoon salt. Nestle fish in tomato mixture.
Bake at 400° for 18 minutes or until fish flakes easily when tested with a fork.
Sprinkle with remaining 1 teaspoon oregano, parsley, and feta.