Prepare beets in a convenient way for you: bake in the oven or boil. (the weight of already boiled and peeled vegetables is given) .
Grate on a fine/medium/coarse grater or on a Korean salad grater.
Put the beets in a deep salad bowl, add the chopped green onions.
For the sauce, mix yogurt, horseradish, honey (preferably liquid) and mustard. Adjust the sharpness of the sauce to your taste! As a base for the sauce, instead of yogurt, you can use thick kefir or yogurt. It'll be fine, too.
Season the beetroot and onion sauce, mix, and add salt to taste.