Heat oven to 450 degrees. Cover the bottom of a baking sheet large enough to hold the fish with parchment paper.
Rinse fish inside and out with cold water and drain. Dry with paper towels. Stuff body cavity with herbs and citrus, saving a few lemon slices for garnish. Set aside.
Pour 1 box of salt into a large bowl, add egg whites and water, then the second box of salt. Use your hands to work mixture to a mortar-like consistency. Lay down a 1/2-inch thick bed for the fish to lay on with a 1-inch clearance on all sides. Lay the fish on this bed and pile the remainder of the salt mortar on top. Work into a smooth dome completely encasing the fish. (Don't worry if the head or tail poke out a little.)
Cook approximately 35 minutes. Check for doneness by pushing the probe of an instant read thermometer through the salt into the fish. When temperature reaches 130 degrees, remove from oven, and rest at room temperature for 5 minutes. Open the fish at the table by hitting the dome several times with a small hammer and lifting off the slabs of salt. Brush away any stray salt. Gently pull out dorsal (back) fin. Using a fish knife or serrated pie server, make a single incision all the way down the back of the fish and around the gill plate. Then lift the skin off working from the head to the tail. Remove meat from top side of fish, going down one side of the spine then the other. Grasp the tail and remove the skeleton, (it should come up intact). The meat revealed below will slide right off the skin.
Sprinkle meat with a little virgin oil and lemon juice. Serve immediately.
Recipe courtesy of Alton Brown