In a large bowl add the beet, cabbage, onion, ginger and salt, and massage well with your hands, until the cabbage softens and leaves its water into the bowl.
Transfer the mixture with the juices into a very clean jar with a lid.
Press the mixture to eliminate air bubbles and cover it completely with its liquid.
Lid the jar and keep onto the counter for about three days, until it smells and taste lightly sour, but clean (you will recognise the smell!)
Refrigerate for two days, then use it to make this salad.
Add the sauerkraut into a large bowl, together with the the rest of the ingredients.
Mix to combine and serve.