Preheat oven to 250 degrees. Place zucchini in a colander over a bowl, and mix with 1/2 teaspoon salt. Allow to drain for five minutes. Transfer to a cloth kitchen towel, and squeeze hard to extract as much moisture as possible. Squeeze a second time; volume will shrink to about half the original.

In a large mixing bowl, combine zucchini and eggs. Using a fork, mix well. Add flour, 1/2 teaspoon salt, olive oil, feta, scallions, dill and 1/2 teaspoon black pepper. Mix well, add baking powder, and mix again.

Place a cast iron skillet or other heavy skillet over medium heat. Add 2 tablespoons vegetable oil and heat until shimmering. Place heaping tablespoons of zucchini batter in pan several inches apart, allowing room to spread. Flatten them with a spatula if necessary; pancakes should be about 3/8 inch thick and about 3 inches in diameter. Fry until golden on one side, then turn and fry again until golden on other side. Repeat once or twice, frying about 5 to 6 minutes total, so pancakes get quite crisp. Transfer to a plate lined with paper towels, and keep warm in oven. Continue frying remaining batter, adding more oil to pan as needed. Serve hot.

For yogurt sauce: In a small bowl, combine yogurt, garlic and salt. Mix well, and serve on the side or on pancakes.