Yes! Ideally, you should place your leftover pork and sauerkraut (with juices) in a large gallon-sized freezer-safe zip-top bag. Place the bag on its side and squeeze out any air.
Storing frozen items this way, keeps freezer burn at bay and allows for more room in your freezer.
Frozen pork and sauerkraut can be thawed in the fridge and warmed via your preferred method (oven or microwave).