Peel the cucumber (I peel half of it, that is my compromise as I can never decide wether to peel or not to peel) and grate coarsely.
Place the coarsely grated cucumber in a colander and mix well with a teaspoon of salt.
Hang the strainer over a bowl or saucepan. After half an hour or more, the cucumber has already "lost" a lot of water.
Squeeze the cucumber, either directly in the colander (press on it with your fist), or, even better, with a tea towel or cheesecloth. To do so, spread out the towel, place the grated cucumber in the middle, gather the ends upwards, and press firmly on the "ball" with the cucumber inside.
Mix the skyr in a bowl until smooth.
Then press the garlic to the bowl, and add olive oil, red wine vinegar, and chopped dill. Stir until everything is combined.
Next, add the grated and squeezed cucumber and stir again.
Place it into the fridge until you are going to serve it.