Place the sausages in a large skillet and add 1/2 inch of water and 1 tablespoon of oil, 1 turn of the pan. Bring the water to a boil over high heat. Reduce the heat to medium and cook off the liquid, 8 to 10 minutes. When the water has cooked off, the oil will begin to crisp the casings. Cook the sausages until browned all over, 2 minutes.
While the sausages are working, heat another large skillet over high heat. Add the remaining 2 tablespoons of oil, 2 turns of the pan, and the apple, onion and cabbage. Toss with tongs; the cabbage will wilt and cook down. Season with the cumin seeds and grill seasoning and cook until the cabbage and onion are tender, 10 to 12 minutes. Pour in the vinegar. (Lean back when you add the vinegar-the fumes can burn your nasal passages a little. Trust me on this.) Scatter the brown sugar over the slaw and toss to combine. Cook off the vinegar for 1 minute and allow the sugar to evenly coat the cabbage. Taste the slaw, adjust the seasonings and turn off the heat. Place the chicken sausages on the toasted buns and top with the warm red slaw-kraut.