Preheat the oven to 425 degrees F. Place the halibut in a single layer on a parchment paper-lined baking dish. Drizzle with the oil/juice; season with salt and pepper. Bake the halibut for 12 to 15 minutes, or until the fish is cooked through.
While the fish bakes, place the remaining ingredients in a food processor and pulse until smooth. Spoon the mixture into a small pot, season with salt, set over medium heat, bring to a slow simmer, and simmer 2 to 3 minutes.
When the fish is cooked, spoon some of the sauce on each of 4 plates. Divide and set a piece of fish on the sauce and serve.