Sort and rinse the beans. Add them to the pressure cooker along with 8 cups of water and 2 tsp. of salt.
Set cook time for 2 minutes. Let the pressure release naturally for 15 minutes, then release remaining pressure.
Remove the pressure cooker pot and drain the beans.
Add the ham bone to the pressure cooker pot, then return the beans to the pot. Add the onion, green pepper, garlic, water, salt, pepper, chili powder, and cumin. Stir to combine.
Set cook time for 30 minutes. Let the pressure release naturally for 15 minutes, then release the remaining pressure.
Remove the ham bone from the pot.
Remove half of the soup and place in the blender. Blend until smooth. Return to the pot and stir to combine. Stir in vinegar.
Serve with diced raw onion and sour cream, if desired.