Heat oil in a Dutch oven over medium heat. Add onion and next 5 ingredients (onion through garlic), and sauté 5 minutes. Stir in water, salt, broth, and beans. Bring to a boil, and cover. Reduce heat, and simmer 45 minutes or until tender.
Place half of bean mixture in a blender or food processor, and process until smooth. Return pureéd bean mixture to pan. Stir in turkey, bell pepper, parsley, sherry, and hot sauce; cook an additional 5 minutes or until thoroughly heated. Ladle soup into bowls, and top with sour cream. Garnish with cilantro sprigs, if desired.