Grate the zucchini. I just use a regular cheese grater (you can also use a food processor).
Place a large colander in your sink, add the grated zucchini and the salt. Toss well, and set let the zucchini mixture rest for about 15 minutes to allow some juices to drip out.
After this time, squeeze as much liquid out of the zucchini as possible using your hands. I like to press down in the colander to press out excess moisture.
Then spread the zucchini out onto a clean tea towel, and squeeze again. The zucchini should be as dry as possible so your fritters aren't mushy.
In a separate large bowl combine the feta cheese, onions, dill and garlic.
Stir in the zucchini and the eggs, and mix well.
Add the flour, corn starch and baking powder and mix well again.
Cooking Option 1: You can cook these fritters with oil in a large fry pan, over medium-high heat. Heat up about 1/4 cup vegetable oil in the skillet. Then drop about 1 heaping tbsp of the batter into the oil. Cook, turning once, until they are golden brown, about 5 minutes. Drain on paper towel. Place the cooked fritters in your oven to keep them warm until they are ready to serve.
Cooking Option 2: You can cook these without oil on a pancake griddle. You may want to give the top of the griddle a light rub with oil so they don't stick. Drop a heaping tablespoon of the batter onto the griddle, and cook them as you would pancakes: turning once, until they are golden brown. Place the cooked fritters in your oven to keep them warm until they are ready to serve.