Sauté the bacon in a large soup pot or Dutch oven until most of the fat is rendered. Discard all but 2 Tbsp of the rendered fat. Add the kielbasa half-moons and sauté for 3 minutes.
While the meat is frying, toast the juniper berries, paprika, caraway seeds, and coriander seeds in a small skillet over medium low heat for 2 minutes until the flavor amplifies. Grind them in a spice grinder and set aside.
Remove the bacon and kielbasa with a slotted spoon to a plate lined with paper towel. Discard all but one tablespoon of the rendered fat. Return the pot to medium heat and sauté the onions and garlic until they are limp and just beginning to brown. Add the carrots and parsnips and toss to combine. Sauté for 3 minutes until the vegetables soften.
Add the tomato paste to the pot and toss to coat the vegetables evenly. Add the toasted and ground spices to the pot and sauté for 2 minutes. Add the chopped tomatoes and horseradish, then lower the heat and simmer, using the back of a wooden spoon to scrape up any bits on the bottom of the pot.
Add the sauerkraut and its juice to the pot, along with the bacon/salo and the stock. Bring the mixture to a low simmer, cover, and cook for 45 minutes. Let the soup sit, uncovered overnight, to allow the flavors to develop. Garnish with generous amounts of fresh dill before serving.
