Slice each zucchini in half lengthwise and scoop out the seeds to create boats, being careful not to pierce the skin.
In a large mixing bowl, combine cooked quinoa, cherry tomatoes, red bell pepper, black olives, feta cheese, dried oregano, garlic powder, salt, and black pepper. Mix until well combined.
Drizzle the olive oil over the mixture and toss gently to coat.
Spoon the filling evenly into each zucchini boat, packing it slightly to ensure they are well-filled.
Place the stuffed zucchini boats on a baking sheet lined with parchment paper.
Bake in the preheated oven for 25-30 minutes, or until the zucchini is tender and the tops are golden brown.
Remove from the oven and let cool for a few minutes before serving.