Place the sauerkraut, cream cheese, Swiss cheese, corned beef, and thousand island dressing in a slow cooker.
Cover the slow cooker and set it to high heat for 45 minutes if you're short on time. If you have more time, set it to low heat and cook for a longer duration until everything is hot and the cheese is melted.
Stir the mixture occasionally while it's cooking.
Once cooked, serve the dish with cocktail rye bread or crackers.