Eid Mubarak to all! May Allah write what is best for the Muslim nation and the whole world.
A famous accompaniment to any Iraqi (or Arab in general) grilled meats and most sandwiches is this onion-sumac relish/pickle.
It's really as easy as it gets: slice some onion by cutting in half, then slicing into thin wedges.
Sprinkle with a tad of vinegar and generously with sumac.
I usually measure by eye, but for one medium onion I would say a tablespoon of vinegar and a heaping teaspoon of sumac.
صحة و عافية