In a large skillet, heat the oil over medium-high heat. Add the bell pepper and onion and sauté until the veggies start to become tender, 1 to 2 minutes.
Add the corn and garlic and sauté for 5 minutes.
Stir in the beans, cilantro, chili powder, salt, and lemon juice (start with ½ of the lemon and add more at the end if you’d like more tang) and cook just until heated through.
Allow to cool for 5 minutes, then serve in lettuce leaves.
