Fatayar are savory Lebanese pies with a thinly rolled dough and flavorful filling. You can play with the filling flavors however you like, adding feta cheese or sesame seeds or pine nuts (you get the idea!). Fatayar freezes well in a ziplock freezer bag and can be reheated from frozen, or simply thaw to room temperature and eat.
Proof the yeast by dissolving it in ¼ cup of the warm water with the sugar and letting it activate for about 10 minutes, or until creamy and starting to bubble.
Whisk together the flour and salt in a mixer bowl or medium bowl. Create a well in the center and add the oil and proofed yeast mixture. Using a stand mixer fitted with the hook attachment (ideal because this is a wet dough) or by hand, slowly work the wet ingredients into the dry, adding the remaining ¾ cup of water slowly. Add more water only as necessary to create a sticky dough.
Knead by hand or with the dough hook in the mixer until the dough is very soft, smooth, and tacky/sticky to the touch (but it should not leave dough on your fingers when touched). The kneading by hand can be awkward at first because it's such a wet mess, but as you knead, the dough will firm up a bit and absorb all of the water.
In a clean bowl at least twice the size of the dough, lightly coat the dough and the sides of the bowl with oil. Cover with plastic wrap and let rise in a warm spot until doubled, about 90 minutes.
While the dough rises, drain the grated zucchini with a pinch of salt in a colander in the sink.
When the dough is ready (90 minutes), squeeze the zucchini to remove as much liquid as possible. Combine the zucchini with the onion, sumac, pepper, and lemon. Taste and adjust the seasonings if needed.
Preheat the oven to 375 degrees. Brush two heavy baking sheets with canola oil (I line them with nonstick foil and brush that with oil; this is optional).
Roll half of the dough out on a dry work surface to ⅛-inch thickness. Gently lift the dough from the edges to allow for contraction. Cut dough into 3- or 4-inch rounds. Knead together the scraps, cover with plastic, and set aside.
Fill the rounds of dough by placing a heaping tablespoon of filling in the center of each round. Be careful not to let the filling touch the edges of the dough where it will be gathered together and closed. A good way to keep the filling in the center is to lower the spoon with the filling over the center of the dough (parallel to it) and use your fingers to slide the filling off the spoon and into the center of the dough circle.
Bring three sides of the dough together in the center over the filling and pinch into a triangle. Close the dough firmly.
Place the fatayar on the baking sheets and generously brush or spray the dough with olive oil. Bake in the middle of the oven for 18-20 minutes, or until golden brown. Set the oven on convection bake for the last 5 minutes of baking to encourage browning. Remove them from the oven, brush with a touch of olive oil, and dust very lightly with sumac immediately.
Repeat the process with the other half of the dough, then with the scraps that have been kneaded together and left to rest for a few minutes before rolling out.