Combine corned beef, sauerkraut, Swiss cheese, Thousand Island dressing, cream cheese, green onions, Dijon mustard and caraway seeds (if using) in a mixing bowl.
Transfer the mixture to a slow cooker.
Cook on low for 3-4 hours, or until cheese is melted and dip is hot.
Stir occasionally.
Season with salt and pepper to taste before serving.
Serve warm with rye bread cubes, crackers, or vegetables.