Japanese potato salads are defined by a mashed potato–like texture, a velvetiness richness from Kewpie mayonnaise, and the crunch of salted and squeezed-dry cucumbers. Some versions include carrots, corn, dashi or even cheese or salmon roe. We highly recommend seeking out Kewpie mayonnaise. The Japanese condiment is creamier and fuller-flavored than American mayonnaise, thanks to MSG and a yolk-only formula. If it is not available, stir 1 teaspoon unseasoned rice vinegar and ½ teaspoon white sugar into ½ cup regular mayonnaise. For soft-cooked eggs, drop cold eggs into simmering water and cook for 6½ to 7 minutes, then transfer to an ice bath. The salad is best at room temperature. It can be made a day ahead and refrigerated in an airtight container, but in that case, stir the entire amount of cucumber mixture into the mix and let the salad stand for 30 minutes at room temperature before serving. Shichimi togarashi is a Japanese spice blend; alternatively, garnish simply with toasted sesame seeds.