Rinse and sort beans according to package directions. Place beans in a large Dutch oven; cover with cold water, and let soak at least 8 hours. Drain beans, and return to Dutch oven. Add 14 cups water, bay leaf, and garlic; bring to a boil over medium-high heat. Cover, reduce heat to medium-low, and simmer, stirring occasionally, 2 hours or until beans are tender.
Process oregano, cumin seeds, and salt in an electric spice grinder until ground and blended.
Sauté chiles in 2 tablespoons hot oil over medium-high heat in a large skillet 5 minutes; add onions, and sauté 5 minutes or until tender. Stir onion mixture and oregano mixture into beans in Dutch oven, and simmer, stirring occasionally, 30 minutes.
Remove and discard bay leaf. Cover and let stand 5 minutes. (For a thicker consistency, remove 1 cup bean mixture, and mash with a fork; return to pan.) Serve over rice, drizzling with oil and vinegar.
*1 large green bell pepper may be substituted.
Note: If you don't have an electric spice grinder, use a mortar and pestle, or place spices in a zip-top plastic freezer bag, seal, and pound with the flat side of a meat mallet.