Heat oil in a large skillet on medium-high heat. Saute onion and garlic for 5 minutes. Stir in chili powder and cumin, and cook 1 minute. Stir in water, tomato, kidney beans and salt. Bring to a boil, then reduce heat and simmer for 20 minutes.
Stir in spinach and cook 5 minutes more. Spoon 1/4 of the bean mixture into the middle of a warm tortilla. Wrap.
To Freeze: Freeze in freezer safe container.
To Reheat: Heat in microwave or oven until hot and garnish with avocado, sour cream and salsa.