Place the apples and onion into the bottom of a slow cooker, and sprinkle with 1/4 teaspoon cinnamon.
Rub the pork roast with salt and pepper, and place it on the layer of apples and onions in the slow cooker. Pour the applesauce over the roast, and dust the top with 1/4 teaspoon cinnamon.
Cook on High setting for 8 hours. Serve the roast topped with the sauce, apples, and onions.