Saute chiles and onion in a stock pot over medium heat until soft.
Add garlic and saute for one minute longer.
Add black beans and stock.
Add salt, black pepper, and red chili if using.
Bring to a simmer and simmer for ten minutes.
Puree using a hand blender, or pour soup carefully into a regular stand blender. Be very careful - soup is hot!
Serve hot, and top with more diced onion and chili, goat cheese, yogurt, sour cream, or other desired topping.