Dice the potatoes and carrots, then boil them.
Blanch the tofu in boiling water and drain the moisture.
Mash the boiled potatoes, carrots, and tofu.
Finely chop the cucumber and onion, salt them, and squeeze out the moisture.
Put all ingredients in a bowl and season with salt and pepper.
Add mayonnaise and mix everything evenly.
Transfer the finished salad to a serving dish.