1Wash and dry arugula leaves. Arrange leaves on a large plate and layer with onions, mushrooms and tomato.
2Whisk together olive oil, lemon juice and sumac. Season to taste with salt, and pour over the salad.
Footnotes
Note
Sumac, available as a ground spice in Middle Eastern markets, comes from the dried berries of a shrub that grows wild in Mediterranean areas. The taste is sour, fruity and astringent.