Boil the chicken breast in salted water, cool, cut into strips.
Cut the onion into thin half rings, marinate (vinegar + salt + sugar + boiling water) for half an hour.
Drain the marinade, lightly squeeze the onion and send it to a bowl with chicken meat.
Add the eggs, cut into small cubes.
Add the sliced cucumbers.
Then sliced tomatoes, greens. Season with mayonnaise, mix. If necessary, add salt and pepper.