Cook or steam the potato and carrot until tender. Dice the cucumber. Mash the potato and mix it with the diced carrot and cucumber, then drizzle with mayonnaise.

Steam the salmon and flake it into small pieces. Boil the egg, peel it, and chop part of it to add to the potato mixture. Reserve some of the egg yolk.

Place the potato salad on a plate in a circular shape. Arrange the salmon pieces around the circle, sprinkle the reserved egg yolk inside the circle, and garnish the center with diced cucumber.