Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Cut each zucchini in half lengthwise. Using a spoon, carefully scoop out the flesh, leaving about 1/4-inch border around the edges. Chop the scooped flesh and set aside.
Brush the zucchini boats with olive oil and season with salt and pepper. Place them cut-side up on the prepared baking sheet.
In a large bowl, combine the chopped zucchini flesh, cooked quinoa, tomatoes, feta, olives, red onion, garlic, lemon juice, oregano, and cumin. Mix well.
Divide the mixture evenly among the zucchini boats, pressing gently to pack the filling.
Bake for 20-25 minutes, until the zucchini is tender and the filling is heated through.
Garnish with fresh parsley before serving.