Sort and wash beans; place in a pressure cooker. Add 10 cups water. Close lid securely; bring to high pressure over high heat (about 7 minutes). Cook 3 minutes. Remove from heat; place pressure cooker under cold running water. Remove lid. Drain beans, discarding liquid.
Return beans to the pressure cooker. Add 10 cups water, salt pork, and garlic. Close lid securely; bring to high pressure over high heat (about 7 minutes). Adjust heat to medium or level to maintain high pressure; cook 1 hour. Remove from heat; place pressure cooker under cold running water. Remove lid.
Discard salt pork. Cool the beans to room temperature.
Drain beans, reserving 1 cup cooking liquid. Heat a large nonstick skillet over medium heat. Add the beans, reserved cooking liquid, and salt. Mash the bean mixture with a potato masher to desired consistency. Cook 5 minutes or until thoroughly heated. Sprinkle with cheese.
Note: To prepare in a pan: Sort and wash beans, and place in a large Dutch oven. Cover with water to 2 inches above the beans; bring to a boil. Cook 2 minutes; remove from heat. Cover and let stand 1 hour. Drain beans. Add beans, 10 cups water, salt pork, and garlic to pan; bring to a boil. Cover, reduce heat, and simmer 1 hour and 45 minutes or until beans are tender. Continue with discarding salt pork and complete the recipe as directed.