Heat oil in a large nonstick skillet over medium heat. Add onion, bell pepper, and garlic; cook, stirring constantly, 4 minutes or until tender. Add tomato sauce; cook 10 minutes or until most of liquid evaporates, stirring occasionally. Add black beans and next 5 ingredients; bring to a boil, stirring frequently. Partially mash bean mixture with a potato masher or fork. Add vinegar; reduce heat, and simmer 5 minutes or until thick, stirring occasionally. Top each serving with sour cream and chopped cilantro. Garnish with cilantro sprigs, if desired.