2 onions, thinly sliced
1 cup chopped mushrooms
1 tomato, diced (Optional)
1 teaspoon extra virgin olive oil
½ lemon, juiced
2 teaspoons sumac (see Note)
Salt to taste
Wash and dry arugula leaves. Arrange leaves on a large plate and layer with onions, mushrooms and tomato. Whisk together olive oil, lemon juice and sumac. Season to taste with salt, and pour over the salad.