Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper, trimmed to extend 3-inches in diameter around outside of the fish.
In a medium bowl, combine the egg whites, sea salt, flour, 2 tablespoons of the parsley and 1/2 cup of water. Mix with your hands until a thick paste forms.
Fill the cavity of the fish with the sun-dried tomatoes, olives, artichoke hearts and lemon slices. Rub the exterior of the fish with the garlic, then sprinkle with the remaining 1 tablespoon of parsley and freshly ground black pepper
Put the fish on the parchment lined baking sheet. Mound the salt paste evenly over the entire fish. Press the mixture firmly down to the baking sheet, being careful to seal any cracks.
Bake the fish until the crust is golden brown and very firm, about 18 to 20 minutes.
Slide the parchment and fish onto serving platter or cutting board and crack the crust with a handle of a large knife. Slide a spoon under the top fillet, over the spine, and lift it to a serving platter. Turn over and repeat. Garnish with lemon slices and serve immediately.