In a mortar, pound the garlic and salt together until mushy. Put the chili peppers and onion in a food processor and chop finely. Add the tomato and process in bursts until it is chopped. Remove to a medium-size bowl and stir in the pounded garlic, tomato paste and cumin. Preheat the oven to 350 degrees. Rinse the fish and pat dry with paper towels. Score the fish in three places on each side. Lay the fish in a baking pan and coat with the olive oil on both sides. Sprinkle with salt and pepper, cover with the chili pepper sauce. Bake the fish until the dorsal fin feels as if it will come off with a tug, about 1 hour, basting with the accumulated olive oil in the baking pan. Sprinkle with the coriander and serve.