In large bowl, toss zucchini slices to coat with 2 Tablespoons olive oil. Set aside. (Do NOT add salt yet.)
Preheat oven to 375℉.
Use two large pieces of parchment paper to roll out pastry dough. When pastry dough is 1/4" thick or less, peel off the top sheet of paper, and transfer bottom parchment paper to baking pan (with dough on top).
Create overlapped rows of zucchini on pastry dough, leaving a 1-1-½" border of pastry around the edges.
When all or most of the zucchini is used, use the edges of the parchment paper to help you fold the pastry dough neatly over the zucchini. This is a rustic pastry, so it doesn't have to be perfect or symmetrical. Fold sides and corners, overlapping, until all the edges are folded over the zucchini.
Sprinkle all of the zucchini with sea salt, to taste. (Don't skip the salt at this stage because it helps the moisture from the zucchini to evaporate when it bakes, preventing soggy zucchini.) Optional, if you're not AIP/VAD and eat eggs, you can brush the pie crust edges with beaten egg to create a more golden crust when it's done baking.
Bake 25 to 30 minutes, until all the edges look golden and crispy, and the zucchini is nicely cooked.
Garlic garnish: While zucchini bakes, optionally fry garlic in remaining one tablespoon olive oil: Heat pan over medium heat. Add olive oil to the center of the pan. Lay slices of garlic into oil. Reduce heat to low. Fry garlic until first side is golden brown, being careful not to burn. Use two forks or similar to flip over, and cook second side the same way. Remove to a plate when golden brown on both sides.
After allotted time, remove galette from the oven. Use a spoon to ladle Lemon Mint Pesto over the fanned zucchini, spreading it nicely. Optionally, also garnish with tiny lemon wedges, cooked sausage and sumac.
Slice and serve.