We’re giving tuna a Mediterranean makeover in this hearty, whole grain salad. Farro, chickpeas, fennel, and arugula get tossed together with tuna and a bright splash of lemon. Feta scattered over the top makes a tasty finish. Serve it as a light supper any day of the week or take it to go, since it packs up beautifully for school or work lunch. Feel free to substitute another hearty whole grain for the farro, such as brown rice, sorghum, barley, or Israeli couscous. You’ll need about one and one-third of a cup of cooked grains in place of the farro.