Put the sausages in a skillet over high heat and add 1/2-inch of water and a drizzle of oil. Bring to a boil, then reduce the heat to medium and allow the liquid to evaporate, cooking the sausages through. Once the liquid evaporates, the oil will help brown and crisp up the casings.
Combine the vinegar, sugar, peppercorns, cloves, bay leaves, and sea salt in a small pot over high heat. Bring to a boil, stir, then lower the heat to medium-low and let the brine reduce for 5 to 6 minutes.
While the brine reduces, combine the cabbage, red onions, and apples in a large serving bowl. Sprinkle with caraway or cumin seed, if you like the flavor.
Pour the hot reduced brine through a strainer over the cabbage mixture in a slow stream. Evenly distribute it, then pour about 1/4 cup of oil over the salad. Season with salt and pepper, to taste, and toss to combine.
Toast the bread. In a small bowl, combine the softened butter with the herbs. Spread the mixture on the warm toast.
Serve the sausages with the toast, slaw salad, mustard, radishes, and pickles.