01 - Heat 1 tablespoon oil in a large skillet over medium-high heat. Add diced potatoes and season with salt, pepper, and garlic powder. Cook stirring occasionally until golden and crisp, about 12-15 minutes. Remove from skillet and set aside.
02 - In a mixing bowl, combine shredded cabbage, grated carrot, green onions, parsley, mayonnaise, Dijon mustard, apple cider vinegar, salt, and pepper. Toss thoroughly until all vegetables are evenly coated. Set aside to allow flavors to meld.
03 - Heat remaining tablespoon of oil in the same skillet. Add shredded corned beef and sauté for 2-3 minutes until heated through and slightly crisped at the edges.
04 - Warm tortillas in a dry skillet over medium heat for 30 seconds per side or microwave in a damp paper towel for 20-30 seconds until soft and pliable.
05 - Build each taco by layering crispy potatoes on the warm tortilla, followed by a portion of warmed corned beef. Top generously with cabbage slaw and finish with a drizzle of sour cream.
06 - Arrange tacos on a serving platter and offer extra slaw on the side. Serve immediately while tortillas are warm and potatoes remain crispy.