Meanwhile make the tzatziki sauce: combine all sauce ingredients and refrigerate. In a large mixing bowl combine zucchini, onion, herbs, flour and feta together. Season well with salt and pepper. Refrigerate 20 minutes.
Heat a large skillet over medium heat with enough olive oil to generously cover bottom. Drop fritters by 1/4 cup full into skillet and use a spoon or spatula to form into patties. Cook on each side about 5 minutes until golden brown. Add more oil to pan as needed, working in batches. Serve with tzatziki sauce.
Original recipe found here.