Preheat your oven to 375°F (190°C). Cut the zucchinis in half lengthwise and scoop out the flesh to create hollow "boats." Set the zucchini flesh aside.

Place the zucchini boats on a baking sheet, brush them with olive oil, and season with salt and pepper. Bake in the preheated oven for about 10 minutes, until slightly tender.

While the zucchinis are baking, heat the remaining olive oil in a skillet over medium heat. Add the chopped onion and garlic, cooking until the onion becomes translucent.

Chop the reserved zucchini flesh and add it to the skillet. Cook for about 5 minutes, then add the cherry tomatoes, cooked quinoa (or couscous), Kalamata olives, and dried oregano. Cook until everything is heated through. Season with salt and pepper to taste.

Remove the zucchinis from the oven and fill each boat with the stuffing mixture. Sprinkle the crumbled feta cheese over the top. If using, also sprinkle some grated Parmesan cheese.

Return the stuffed zucchinis to the oven and bake for an additional 10-15 minutes, until the cheese is melted and bubbly.

Garnish with fresh parsley and basil before serving.