Drain the beans and add fresh water to cover. Add 1/2 teaspoon salt and a splash of lime juice and cook until tender. If preparing on a stovetop, bring to a boil, cover and lower heat to simmer. Cook for about 1 1/2 hours, checking liquid levels and adding more water if needed. If using a pressure cooker, it's 3 minutes at 15 PSI and slow release.
Coat the bottom of a soup pot with the oil and add 1/2 teaspoon salt, cumin and chili powder. Cook on medium heat for about 30 seconds to release the aromatic smell, don't let it smoke.
Add the onion. Stir and cook for about 10 minutes. Add the pepper and continue to cook for another 10 minutes. Add the cooked black beans and liquid to the pan. Bring to a simmer and cook for 10-15 minutes. Add lime juice and optional cilantro befor serving.
Serve with Orange and Blueberry Salsa and rice.