In a large soup pot, heat olive oil over medium-high heat. Add onions and cook, stirring, until they start to sweat, about 5 minutes. Add garlic and both the sweet and hot pepper.
Stir to combine and reduce heat to medium. Cook the vegetables, stirring occasionally, for another 15 minutes, until they're softened and aromatic.
Add the black beans. Stir to combine. Reduce heat to medium, set the pot lid on halfway, leaving a little steam vent.
Cook the beans for an hour, longer if you've got the time. Add a quarter cup of water if necessary. The beans should be thick but not over-dry. The goal is a divine beanly sludge.
Stir in the tomato paste, smoked paprika and sherry or cider vinegar. Remove from heat.
Add the chiffonade of kale or chard by the handful. Stir gently, letting the greens wilt into the beans.
Season with sea salt to taste.