Place beans, water, onion, garlic, chicken base, cumin, salt, pepper, and cayenne in crock pot. Cook on high until beans are tender (8 hours or so).
Heat the lard in large skillet over medium-medium high heat.
Drain beans and add to skillet. Mash the beans coarsely with the back of a wooden spoon, adding more chicken broth if needed, to moisten.
Stir in the cilantro and lime juice.
Top with shredded cheese.