Place chicken in a resealable plastic bag set in a shallow dish. For marinade, combine orange peel, the 1/3 cup orange juice, the 4 cloves garlic, honey, and thyme. Pour over chicken; seal bag. Marinate in the refrigerator for 6 to 8 hours, turning bag occasionally.
Drain chicken, discarding marinade. Place chicken on the unheated rack of a broiler pan. Season with half of the salt and half of the black pepper. Broil 4 to 5 inches from heat for 12 to 15 minutes or until chicken is no longer pink (170 degrees F), turning once halfway through broiling.
Meanwhile, for dressing, in a screw-top jar combine olive oil, vinegar, the 2 tablespoons orange juice, the 2 cloves garlic, shallots, and remaining salt and pepper. Cover and shake well.
Divide greens among four dinner plates. Top with sweet pepper slices. Slice chicken crosswise. Arrange chicken and orange sections over greens. Drizzle with dressing.