1. Place potatoes in a pot, cover them with water and bring to a boil. Cook for about 20 minutes, or until potatoes are easily pierced with a knife. Drain and let cool.
2. In the meantime, place eggs in a pot, fill it with cold water to cover the eggs. Bring the water to a boil. Reduce the heat and boil the eggs for 10 minutes to get hard boiled eggs. Chill them by placing under cold running water or in a bowl of ice water.
3. In a bowl, whisk together cold water and sour cream, add vinegar and salt, mix well. Put in the fridge.
4. Peel and dice the potatoes. Dice the eggs.
5. Add all the rest of the ingredients to the bowl with the Okroshka base. Stir and enjoy!