Heat oil in a saucepan over medium heat.
Saute onion, celery, carrot, and cyan pepper for about 5 mins or until soft.
Add cumin and garlic and cook for another minute.
Stir in spinach and drained tomatoes and cook for 5 mins.
Stir in black beans, quinoa, and water.
Cover and bring to a boil.
Reduce heat and simmer for about 20 mins or until quinoa is tender.
salt and pepper to taste.
Preheat over to 350 and pour reserved liquid from the tomatoes into a baking dish.
Fill each 1/2 of bell pepper with quinoa mixture and place into the baking dish.
Cover with aluminum foil and bake 40 mins.
Drizzle juices over the peppers when serving them.