First, peel and dice the onion and fry in a little oil.
Meanwhile, peel the cucumber, cut into strips or smaller cubes and then add to the roasted onion. Cover and let it steam for a few minutes.
Now pour in the soup and add about 1-2 tablespoons of vinegar. Finely chop the dill and add it as well.
Season with salt and pepper and let it steam covered until the cucumber is soft.