Place the beans in a medium bowl and lightly mash with a fork. Add in the lime, garlic, onion, chipotle, adobo sauce, salt and pepper and mix well. If you prefer burgers that are less spicy, you can skip the chipotle or adobo sauce (or both!).
Take a quarter of the mixture and form a tight patty. I like to roll the beans in a ball in my hands and then flatten to my desired thickness. The burgers should keep their shape, but if for some reason, it feels crumbly around the edges, place the patty back in the bowl and add an egg to the mixture to help with binding. Form four patties.
Heat a large griddle or skillet on medium high and coat with the oil. Add your patties and if there is room, the mushroom caps as well. Cook the patties for about 3 - 4 minutes per side or until the outside is a little crispy. The mushrooms take about 2 3 minutes per side.
Toast your burger buns if desired. Place the black bean burgers on the buns and top with the mushrooms and cheese. Add any additional toppings you desire.