Whisk all Dill Yogurt Sauce ingredients together in a bowl. Cover and allow to rest in refrigerator while preparing patties.
Sprinkle 1/2 tsp salt over zucchini, toss and let rest 5 minutes. Using paper towels or a sieve, press excess liquid from zucchini. Place zucchini in a mixing bowl.
Add egg, egg yolk, lemon zest, garlic, flour, feta and 1/2 tsp salt (or less to taste), and toss to evenly coat. Mix in parsley, green onions and dill. If batter is very wet, mix in more flour by the spoonful.
Heat 2 Tbsp olive oil and 2 Tbsp corn oil in a large skillet over medium heat. Working in batches, carefully drop batter about 3 Tbsp at a time into skillet (I just used a 1/4 cup and filled 3/4 full, I also flattened them a little with the back of a measuring cup once in the skillet).
Fry patties until golden brown on bottom, then carefully flip and cook opposite side until golden. Transfer to paper towels to drain. Add more oil as needed and continue to fry in batches. Serve warm with Greek Yogurt Sauce.