There are many countries who have salads similar to this, Iraq and Turkey being just two examples.
It is named farmer's salad, or peasant's salad, because it consists of the most available and basic ingredients: tomato, cucumber, and onion.
Fresh mint with the sumac escalates the flavor of the salad, but if fresh is unavailable, dry mint is used as well.
1 handful fresh mint
1 tsp sumac
1 tsp salt
4-5 Tbsp olive oil
Dice the tomatoes, cucumbers, and onions as coarse or as finely as you like.
Roughly chop the mint and add.
Add the sumac and salt, toss.
Add the olive oil and toss.
صحة و عافية