This is a real workhorse of a recipe: a cheap, virtually instant supper that is yummy and nutritious. I have always felt profoundly nourished by an honest plate of beans and rice, but you may want to make the beans and scoop them up with warmed tortillas or wrap them up with cheese into plump little burritos. Of course, if you need to make these beans this minute and have no smoked anything in the house, you can add cumin or regular paprika or both, and they will still be very good.
Warm the oil and garlic together in a medium pan over medium-low heat, until the garlic is sizzling and fragrant but still nice and pale. Add the tomato paste and paprika or chipotle puree, and fry for a few seconds, then dump in the beans with their liquid and add the greens if you're using them.
Cook the beans uncovered, stirring frequently, for 10-15 minutes, until everything looks united, and the liquid has mostly cooked off.
Now season them with the vinegar and taste for salt: this will depend on your beans. I tend to add about a teaspoon of kosher salt (which is the equivalent of ½ teaspoon table salt), but you may need less: the beans should be saucy and highly seasoned, since you'll be mixing them with bland rice or bland tortillas.
Serve with grated cheese and sour cream (and extra chipotle puree or hot sauce for thems that likes it).