Heat a large heavy pot over medium high heat. Add the bacon to the pot, cook until bacon is crisp. Remove the bacon and set aside for later.
Season the pork with salt and pepper. Add the pork to the pot, being mindful not to overcrowd. Brown pork on all sides, about 5 minutes per side. Remove from pot and set aside.
Add onions and 1 tsp salt to the pot, and cook until the onions have softened, about 7 minutes.
Add the wine and cook until reduced by half, then add the tomato paste, tomatoes and chicken stock. Add the pork, beans, garlic and sausage to the insert of a slow cooker, then pour in the contents of the pot.
Cook on Low for 9-10 hours. Skim off some of the fat, remove the garlic and fold in the parsley. Let stand at room temperature for 30 minutes before serving. Serve topped with the reserved bacon.