Japanese Potato Salad

Bahan-bahan (6 porsi)

• 2 russet potatoes ((1.15 lb, 520 g))
• 2 tsp Diamond Crystal kosher salt ((for cooking the potatoes))
• 2 inches carrot ((2 oz, 60 g))
• ¼ cup frozen or canned corn
• 1 large egg (50 g w/o shell)
• 1 Persian cucumber ((or ½ Japanese cucumber; 3 oz, 90 g))
• ½ tsp Diamond Crystal kosher salt ((for the cucumber))
• 2 slices Black Forest ham ((1.9 oz, 54 g))
• 1 Tbsp rice vinegar (unseasoned)
• freshly ground black pepper ((to taste))
• 6 Tbsp Japanese Kewpie mayonnaise ((divided; add 4 Tbsp first, then add more to taste))