1. Clean the dried chilies by removing the stem and seeds. Careful, use rubber gloves for this! Soak the chili pieces in 1½ cups hot water, covered, for 1 hour.
2. Place them in a blender along with the water, garlic, and salt. Puree and set aside.
3. Heat a medium frying pan and add the oil and onion. Saute until the onion is clear and then add the cumin and browned flour.
4. Stir for a moment and add the tomato. Saute until all is tender, about 5 to 6 minutes. Add the chili mixture, Chicken Stock, and red wine vinegar.
5. Simmer, uncovered, for 5 minutes, stirring until the sauce thickens.
