In a large bowl add chopped zucchini, tomatoes, green onions, red onions, salt, pepper, cayenne, garlic salt, egg whites and mustard. Stir to combine. Add cooked quinoa. Stir again and sprinkle in cheese. Pour batter into mini muffin tins that have been sprayed with Pam. Bake for about 25 minutes or until the tops are golden and set.