In a large bowl, combine the zucchini and feta, then stir in the eggs, green onions and half the garlic clove.
Stir in the flour, baking powder, and some salt and pepper.
In a large, heavy skillet, heat a generous drizzle of oil over medium-high heat.
Drop the batter in large spoonfuls and cook for a few minutes, until the bottoms are golden, then flip and cook for another couple minutes on the other side.
Stir the rest of the garlic into the yogurt along with a pinch of salt, and serve alongside the fritters.