Source: Marisco Tino's Restaurant - Puerto Vallarta, Mexico

Fish
3/4 cup light soy sauce
1/2 cup olive oil
1/3 cup fresh lime juice
4 fresh serrano chiles, finely chopped
1 tablespoon dried oregano leaves
1 tablespoon black peppercorns
4 pounds whole fish (red snapper, sea bass, porgy
    or mullet) cleaned, cut along the spine and scaled

Sauce
4 cups water
1 1/2 pounds ripe tomatoes, chopped
8 fresh serrano chiles
3 large cloves garlic, peeled
1 medium white onion, peeled and quartered
Salt to taste

Garnish
2 cucumbers, peeled and thinly sliced
2 medium white onions, peeled and thinly sliced
Hot corn tortillas

To do this over a wood or coal fire, you will need 2 pounds charcoal or wood. Light the fire and let burn until white ash forms on the coals and flames subside. The fish should be cooked over a gentle fire.

Prepare the fish: Combine soy sauce, olive oil, lime juice, chiles, oregano and black peppercorns. Place the fish in a shallow baking dish and pour the marinade over the fish and let stand for 30 minutes.

Cook the fish over a low fire and baste with marinade. Continue basting until fish is cooked. Skin must be crisp and the flesh should be moist and flaky.

Meanwhile, prepare the sauce: Bring the water to a boil in a medium saucepan. Add the tomatoes, chiles, garlic and onion and cook uncovered for 20 minutes. Cool and puree the sauce in a blender or a food processor. Season with salt.

To serve, transfer the fish to a large platter and cover with the tomato sauce. Garnish the edges of the platter with the cucumber and onion slices and serve with freshly made corn tortillas.

NOTE: The fish could also be broiled in the oven, just do it more slowly than you would a steak or other meat.