Add bacon slices to a dutch oven and cook over medium-high heat until crispy. Remove bacon, crumble and set aside. Discard all but 1 TBSP of the bacon grease from the dutch oven.
Set aside 1/4 cup of the diced red onion for topping the soup. Add the remaining diced onion to the dutch oven with the bacon grease and cook over medium-high heat, stirring occasionally, until softened, about 4 to 5 minutes. Stir in the garlic and cook for about 20 seconds or until garlic becomes fragrant.
Carefully pour in the cans of beans and the chicken broth. Stir in the smoked paprika and bring to a boil then reduce heat to low and simmer 10 minutes.
Take off the heat. In batches add the soup to a blender or food processor and pulse until smooth. Return all the soup to the dutch oven, add salt and pepper to taste and if necessary warm to desired temperature.
Serve soup topped with sour cream, the reserved red onion and crumbled bacon.