2 skinless, boneless chicken breast halves (about 1 1/4 pounds total)
7 tablespoons prepared Italian dressing, divided
2 bell peppers (red or green, or 1 of each), quartered
1/4 small red onion, thinly sliced
6 lightly packed cups arugula leaves
Split the chicken breasts by placing them on a cutting board and using a sharp knife to slice evenly through them, while applying slight pressure on top with the other hand.
Prepare a grill for medium-high heat cooking. Brush chicken breasts on both sides with 3 tablespoons of dressing. In a small bowl, toss bell peppers with 2 tablespoons dressing. Grill chicken and peppers, turning occasionally, until chicken is cooked through and peppers are tender and browned, 6 to 7 minutes. (Take care that raw chicken does not touch the peppers.)
Meanwhile, toss onion and arugula with remaining 2 tablespoons dressing and arrange on a platter. Slice chicken and peppers; place them on top of arugula.
Per Serving:250 calories (100 from fat), 11g total fat, 1.5g saturated fat, 90mg cholesterol, 480mg sodium, 5g carbohydrate (2g dietary fiber, 3g sugar), 32g protein