Preheat oven to 450
Place grated zucchini in a cheesecloth or clean, thin dishtowel, and squeeze out as much liquid as possible
In a medium sized bowl, combine zucchini, egg, one-third cup Mozzarella cheese, and Italian seasoning
Form zucchini mixture into a rectangular shape(~1/3 inch thick) onto a parchment-lined baking sheet, or onto a silicone baking mat on top of a baking sheet.
Bake until edges are nicely browned, about 20-25 minutes.
Meanwhile, prepare marinara sauce. In a blender or food processor, puree diced tomatoes, garlic, and salt until smooth.
Remove crush from oven once done, and reduce oven temp to 400. Sprinkle top with remaining Mozzarella cheese and garlic salt.
Bake until cheese is melted, about 7-10 minutes. Let cool, then cut into breadstick-shaped pieces.
Serve with marinara sauce.