Peel and finely chop the onion. Drain beetroot and chick peas well. Cut beetroot into slices. Wash apples, grate dry and cut into slices as well. Coarsely crumble the feta.
Mix vinegar, sugar, salt, pepper and mustard. Add the oil in portions. Wash the chives, shake dry and cut into fine rolls. Mix onion, beetroot, chickpeas and apples.
Carefully fold in the vinaigrette. Sprinkle with feta and chives.