
Preheat the oven to 300 degrees F.
Generously season the halibut on both sides with salt and pepper.
Heat an oven-safe skillet over medium-high heat. Add the halibut to the hot skillet and sear one side until a golden crust forms, about 2 minutes. (Do not cook the halibut completely.) Transfer the halibut to a plate and set aside.
With the skillet still over medium-high heat, add the tomatoes, garlic, and salt. Cook the tomatoes until some start to burst, about 4 to 5 minutes.
Nestle the halibut in the burst tomatoes with the seared side facing up.
Bake until the fish is cooked through, about 10 to 15 minutes.
Squeeze the lemon wedges over the dish and spoon the pesto over the halibut. Serve immediately.