Shred the lettuce leaves into bite-sized pieces and transfer them to a bowl. Wash and chop peppers, tomatoes, and radishes. Peel and chop the onion. Add everything to the salad.
Dressing:
Put the yogurt in a mixing cup. Wash and cut the chives and add them. Add sugar, lemon juice, pepper and salt to taste. Add the oil and mix well.
Just before eating, you pour the dressing over the salad and mix it thoroughly.