Put the zucchini in a fine-mesh sieve, sprinkle with 2 tsp salt, and let stand for 15-30 minutes. Squeeze out any excess liquid.
In a small bowl, stir together the flour, baking powder, ¼ teaspoon pepper, and 1 teaspoon salt.
In a separate medium sized bowl, stir together the zucchini, feta, egg yolks, green onions, and parsley. Stir in the flour mixture.
In a clean bowl, beat the egg whites to soft peaks. Fold into the zucchini mixture.
In a frying pan over medium heat, warm the olive oil. Drop 4 spoonfuls of batter into the pan, spreading them out slightly with your spoon so they are thin and round.
Fry until crisp, about 1 1 /2 minutes per side. Transfer to paper towels, season with salt, and keep warm.
Add more oil to the frying pan and fry the remaining batter.