Step 1 Heat the oven to 400 degrees. Line a jellyroll pan with parchment paper. Stuff the cavities of the fish with the bay leaves.
Step 2 Place the salt in a large bowl and stir in the water until the texture is that of gritty snow. On the lined jellyroll pan, spread some of the salt in a layer about 1/4-inch deep that is roughly the size of both fish. Place the fish on top of that, then mound the rest of the salt on top, covering them completely in a smooth, even layer. Roast the salt-encased fish in the oven for 20 minutes.
Step 3While the fish is roasting, prepare the salsa. Cut the tomatoes in quarters and place them in a bowl with the onion, garlic, serrano pepper, capers, olives, oregano and parsley. Mix in the olive oil and lime juice, and season with 1 teaspoon salt or to taste.
Step 4After 20 minutes, remove the fish from the oven and let stand 5 more minutes to finish cooking. With a sturdy metal spoon or chef's knife, chip a crack around the base of the salt crust and carefully lift off the top. Use a dry pastry brush to brush away any salt on the surface of the fish.
Step 5Using a long spatula, carefully lift the fish onto a serving platter, turning it over in the process so you can brush away the salt on the underside. If you prefer, you can skin the fish — the skin will be quite loose and will come up easily.
Step 6Use the spatula to remove the nest of bones under the dorsal fin. Carefully lift off the top fillet, using the tip of the spatula to cut from the top of the fish along the backbone. Carefully lift the fillet to a second, warm serving platter, skin-side down, and remove any loose bones that are still attached.
Step 7Lift the tail of the fish, and the spine and ribs will come free. Cut behind the head again to free the second fillet. Transfer this fillet to the platter, skin-side down, and remove any loose bones. Spoon some of the sauce over the fillets and pass the rest at the table.