Preheat oven to 375 degrees Fahrenheit.
Trim the ends off the zucchini, then slice in half lengthwise. Using a small spoon, carefully scoop out the flesh and seeds, leaving a ¼ inch around the edges to create the hollowed out “boat.” Discard flesh and seeds.
Place the zucchini halves on a rimmed baking sheet. Set aside.
In a large bowl combine the cooked quinoa, cooked chickpeas, diced cherry tomatoes, diced red bell pepper, minced parsley, minced garlic, diced onion, crumbled feta, lemon zest, zaatar and olive oil. Stir until well combined. Season with salt and pepper to taste.
Fill each zucchini half with the stuffing. Bake for 40-50 minutes, until the zucchini is cooked through.
Whisk together the tahini, water, lemon juice, minced chives and ¼ teaspoon salt.
Drizzle some of the tahini mixture over the top of each zucchini boat before serving.