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.