Dice the red onion. Dice the green pepper. Place them in a bowl with 1 ½ cup corn. Drain and rinse the black beans. Mince the chipotle chili pepper (if using).
In a large skillet, heat the olive oil over medium heat. Add red onion, green pepper, and corn, and saute for 5 minutes, stirring occasionally. Add black beans and the oregano, cumin, paprika, liquid smoke, and kosher salt, and a few grinds fresh ground pepper. Add ¾ cup water and let simmer until water cooks down, about 5 minutes.
Meanwhile, remove the lettuce leaves and wash and dry the lettuce.
To serve, spread guacamole on a lettuce leaf, then top with black bean filling and mango salsa. If desired, serve with homemade tortilla chips.
Notes
The prep time below does not include making the mango salsa and guacamole homemade. Be sure to plan timing accordingly.