Heat the olive oil in a frying pan over medium heat. Add the black beans, water, cumin, smoked paprika, chili powder, cayenne, and Mexican oregano. Then season with salt and black pepper to taste, and stir to combine.
Cook, occasionally stirring, until the beans are warmed throughout, and the spices become fragrant; around 4-5 minutes. Remove from heat then set to the side.
While the beans cook, mash the avocado in a small glass or other non-reactive bowl. Add tomato, fresh cilantro, lime juice, and jalapeño. Season to taste with salt and black pepper, then stir to combine. Set aside.
Transfer the warm beans to a bowl and add the optional diced bell pepper if using. Scoop individual portions of the beans into large lettuce leaves for wrapping, along with fresh guacamole and mango salsa. Serve immediately. Enjoy!