How to Make It
In a large pot of salted water, bring the potatoes to a boil. Cook the potatoes over moderately high heat until tender when pierced with a fork, about 30 minutes. Drain and pat dry.
Working with 1 potato at a time and using a small plate, press down to flatten the potatoes to a 3/4-inch thickness, keeping them intact.
Arrange the smashed potatoes on large serving platters. Season the potatoes with salt. Top each smashed potato with a dollop of sour cream and 1 teaspoon of salmon caviar. Garnish with the chives and serve at once.