Cut the cucumber in half and peel one half, cut both halves into small cubes, set aside.
In a large mortar, crush the garlic and salt, add 75 walnuts and bread crumbs. Crush the mass until smooth. Then add walnut oil or sunflower oil, stir well with a pestle.
Transfer the contents of the mortar to a large bowl, add the yogurt, and mix well. Put the diced cucumber into this mass.
Pour cold mineral water and lemon juice over the mass, stir.
Serve the cucumber soup on serving bowls, sprinkle with walnuts, dill, and olive oil.