Preheat the oven to 450 degrees F (230 degrees C). Grease a baking dish.

Place potatoes in a microwave-safe dish. Microwave on high until just softened, about 5 minutes.

Whisk oil and vinegar together in a mixing bowl. Whisk in paprika and salt, then stir in green onions and jalapeño.

Stir in cooked potatoes until coated. Slide sea bass fillets into the bowl, turning several times to coat with vinaigrette. Transfer fish to a plate.

Transfer potatoes to the prepared baking dish, then nestle fish on top. Sprinkle with a pinch of salt and a pinch of paprika, then drizzle with a bit of oil.

Bake in the preheated oven until fish flakes easily with a fork, about 15 minutes.

Enjoy!