Step 1

Place black beans into a large container and cover with several inches of cool water; let stand 8 hours to overnight. Drain.

Step 2

Place beans in a pot and add enough water to cover; bring to a boil. Reduce heat to medium-low and simmer beans until very tender, about 1 hour.

Step 3

Heat oil in a skillet over medium; cook and stir onion and garlic until onion is soft and translucent, about 10 minutes. Add black beans, green chiles, chili powder, and cumin; cook and stir until flavors blend, about 5 minutes.

Step 4

Blend black bean mixture in a food processor until smooth. Add tomato paste, chicken broth, vinegar, and salt; blend until desired consistency is reached. Return beans to pot and cook until heated through, about 5 minutes more.