This is a very loose recipe and you can alter the amount of each ingredient to your liking.
Slice the onion. Peel (optional) and chop potatoes into bit sized (or a little bigger) pieces. (use whatever type of tater you have on hand. Obviously, you'll need more if you use little reds or yukon golds). Chop kielbasa into 1 inch pieces. Set aside.
In a large skillet heat oil over medium heat to cook onion and taters together. Cook until taters are just about tender and then add about half of the jar of sauerkraut and about half of the jar of sweet and sour red cabbage. It's ok if some of the juice from the jars goes in the pan, but be careful because you don't want to make it soupy. Add the kielbasa. Gently stir this around a bit. Turn the heat down to low and just let this simmer while the kielbasa and the sauerkraut are heating up.
I serve this dish with a little dollop yummy mustard on the side for dipping. Enjoy!