Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly grease it.
In a large mixing bowl, combine cooked quinoa, chopped kale, diced onion, salt, chili powder, black pepper, crumbled feta, panko breadcrumbs, and beaten eggs.
Mix thoroughly with your hands or a spoon until evenly combined; if the mixture seems too wet to hold together, add a teaspoon of flour at a time until it firms up.
Form the mixture into 8 even patties and arrange them on the prepared baking sheet.
Brush the top of each patty with half of the olive oil. Bake for 15 minutes.
Carefully flip each patty, brush with the remaining olive oil, then bake for an additional 10 minutes or until golden and crisp.
Let the fritters cool slightly on the baking sheet before serving.