Preheat oven to 350°. Place vegetable oil in skillet over medium-low heat. Add onion and garlic; cook 3 minutes. Add tomatoes, jalapeño, and wine. Reduce sauce to 1/3 cup (1215 minutes). Meanwhile, heat olive oil in an ovenproof skillet over medium-high heat. Season halibut fillets with salt. Add fish to hot skillet. Cook until undersides brown (23 minutes). Flip fish. Bake 10 minutes. Remove sauce from heat; mix in olives. Divide sauce among 4 plates; top with fillets and avocado slices, juice from 1 lime, and chopped parsley or cilantro.