Mash 1/4 of the black beans in a small saucepan, and stir in salsa, ground cumin, and remaining whole beans. Bring mixture to a simmer over medium heat, and cook for 3 minutes, stirring frequently. Stir in shredded cheese, chopped fresh cilantro, and fresh lime juice, and cook mixture over medium heat until cheese melts, stirring frequently.
Transfer bean dip to a serving bowl, and garnish with additional shredded cheese if desired. Serve bean dip warm or at room temperature with crackers.
Servings: 3 1/2 cups