Cut eggplant crosswise into roughly 8 thick slices (at least 1/2-inch thick). Discard small ends, or cook separately. Places slices over double-layer of thick paper towels. Generously sprinkle both sides of eggplant slices with salt. Let stand for at least 30 minutes to draw out excess moisture. Rinse under water to remove salt and pat dry.
Preheat oven to 350 F. Line a large baking sheet with parchment paper or foil, and grease. In medium bowl lightly beat egg whites. In separate large bowl, combine bread crumbs, Parmesan cheese, garlic salt, and Italian seasoning. Dip eggplant slices into bowl with egg whites, coating both sides. Dip into bowl of breading, press down and flip to coat both sides.
Place slices onto baking sheet. Sprinkle with remaining bread crumbs if there is any eggplant still exposed. Bake for 15-18 minutes until tops are slightly browned. Carefully rotate slices and bake 15-18 minutes more until eggplant is tender. Spoon pizza sauce over tops, sprinkle with mozzarella cheese. Bake 10-12 minutes more until cheese is melted and eggplant is completely cooked through.