Heat oil in a 12-inch nonstick skillet over medium heat. Add the onion, bell pepper, and jalapeño and cook until the onion is softened, about 4 to 6 minutes.

Stir in the garlic, cumin, and salt and cook until fragrant. Add the beans and cook until warmed through, about 1 minute, then transfer the mixture to a large bowl and wipe the skillet clean.

Heat the remaining oil in the empty skillet over medium-high heat until the oil is shimmering. Add the corn and salt, then cook without stirring until the corn is browned on the bottom and beginning to pop, about 3 minutes.

Stir the corn and continue to cook, stirring only once or twice, until the kernels are spotty brown all over, 2 to 3 minutes.

Transfer the corn to the bowl with the black bean mixture. Stir in the cilantro and lime juice, then season with additional salt and lime juice to taste. Serve warm.