Preheat oven to 350°F. Rinse quinoa under running water in a fine mesh strainer and cook according to package directions with 1/2 tsp salt.
In a large skillet, heat the oil and add the onion. Cook until slightly softened, about 4 minutes. Add cherry tomatoes and cook until they start to blister, pop and release their juices, about 5 more minutes. Lightly mash them with a wooden spoon or spatula.
Take the pan off the heat and add in the cooked quinoa, garbanzo beans, capers, 2 Tbsp parsley, za'atar, remaining 1/2 tsp of salt, and pepper, and stir to combine. Add the artichokes and 3/4 of the feta (3 oz.) and carefully fold in, trying not to break them up.
Cut the bell peppers in half lengthwise and remove the ribs and seeds. Arrange cut-side up in a 9x13 baking dish, and use a large spoon to divide the filling mixture evenly among the pepper halves.
Carefully pour 1/2 cup of water into the bottom of the baking dish. Cover tightly with foil and bake for 45-55 minutes, until the peppers are tender but not mushy.
Sprinkle reserved 1 oz feta and 1 Tbsp parsley over peppers. Top each pepper half with 1 Tbsp tzatziki and serve.
Mediterranean Stuffed Peppers https://yummynoises.com/mediterranean-stuffed-peppers/