Thinly slice the cucumber and onion. Place both in a bowl and sprinkle with ½ teaspoon of salt. When they are wilted, squeeze them out tightly, discarding the moisture.
Dice the carrot (raw or boiled) into small pieces (peel, if desired)
Dice the ham into small pieces.
Put the boiled potatoes in a bowl and mash roughly using a fork or spoon, leaving lots of lumps. Add the milk, sugar, chicken bouillon powder, salt and pepper to taste while it's warm. Mix and leave to cool down a little.
Add mayonnaise & mustard, and mix.
Add the carrot, cucumber, onion, and ham and mix loosely.
Cover and chill in the refrigerator.