Grate the zucchini on the large holes of a grater onto a clean kitchen towel. Sprinkle with the kosher salt and let it rest while you gather and prep the remaining ingredients.
Wrap the zucchini in the towel and ring as much liquid out as possible, discarding the liquid. In a medium bowl, combine the zucchini, mint, dill, scallion, garlic, pepper, feta, and all but 1 teaspoon of the lemon zest. Stir in the egg and flour and mix until well combined.