Mix Butter Topping: In a medium bowl, stir together the herb garlic butter, raisins, capers, 1 tablespoon of the chopped chives, and the lemon zest until well combined. Set aside.
Season Salmon: Sprinkle the salmon fillets with ½ teaspoon of the salt and ¼ teaspoon of the black pepper.
Cook Salmon: Heat 1 tablespoon of the canola oil in a large skillet over medium-high heat. Add the salmon and cook for 3 to 4 minutes per side, or until browned on the outside and the fish flakes easily with a fork.
Build Potato Mixture: In a large bowl, combine the grated cheddar, the remaining 1 tablespoon chives, the sauerkraut, and the mashed potatoes. Add the remaining ½ teaspoon salt and ¼ teaspoon black pepper, then mix until evenly combined.
Shape Potato Cakes: Form the potato mixture into 6 small patties of equal size. Place them on a sheet pan or tray.
Coat Potato Cakes: Press each patty into the breadcrumbs, coating both sides evenly.
Fry Potato Cakes: Heat the remaining 1 tablespoon canola oil in a skillet over medium heat. Cook the potato cakes for 3 to 4 minutes per side until golden brown and crisp.
Serve: Place the salmon on plates and spoon the herb garlic butter topping over the hot fillets. Serve the Irish cheese potato cakes alongside.