Step 1

Place each chicken piece between plastic wrap and pound with flat side of a meat mallet until 1/2 inch thick. Place chicken in a resealable plastic bag set in a shallow dish. For marinade, in a small bowl combine the next four ingredients (through garlic); pour over chicken. Seal bag; turn to coat chicken. Marinate in the refrigerator 1 to 2 hours, turning bag occasionally.

Step 2

Drain chicken, discarding marinade. Lightly sprinkle chicken with salt and pepper. Heat a grill pan over medium heat. Add chicken (in batches if necessary); cook 9 to 11 minutes or until done (165°F), turning once. Remove from pan.

Step 3

Meanwhile, cut flatbread into four wedges; cut in half horizontally. Add bread, cut sides down, to grill pan; cook 2 minutes or until toasted.

Step 4

Spread toasted sides of bread wedges with Roasted Pepper and Goat Cheese Spread. Layer chicken, spinach, and red onion between wedges.