Start by peeling and cubing the Yukon Gold potatoes into bite-sized pieces. In a large pot, bring salted water to a boil over medium-high heat. Add the potato cubes and cook for 15-20 minutes, until they are fork-tender but not mushy. Once cooked, drain the potatoes and let them cool slightly in a large bowl.

While the potatoes cool, grab a mixing bowl and combine 1/2 cup of mayonnaise, 2 tablespoons of gochujang, 1 tablespoon of Dijon mustard, and 1 tablespoon of sesame oil. Whisk these ingredients together until the mixture is smooth, creamy, and well-blended.

Next, gently fold in 1 cup of chopped Napa cabbage kimchi and 2 chopped scallions into the dressing. Ensure each piece of kimchi is coated well. Once combined, add the cooled potato cubes to the mixture and carefully mix everything together.

After mixing, cover the bowl with plastic wrap or transfer the salad to an airtight container. Place it in the refrigerator for at least 1 hour to allow the flavors to meld beautifully.

When ready to serve, give the salad a gentle stir and garnish with additional sliced scallions on top.