Make 3 deep slashes in the flesh of each of the chicken pieces. Mix together the maple syrup, soy sauce, sesame oil and Chinese five spice powder in a large mixing bowl, add the chicken thighs and toss to coat. Transfer to a roasting tin and pour over any of the remaining marinade. Roast in a preheated oven, 200°C (400°F), Gas Mark 6, for 25 minutes until the chicken is golden and cooked through.
Meanwhile, make the salad. Place the cucumber, sweetcorn and red pepper in a bowl and toss well.
Add the French dressing and toss well again, seasoning with pepper. Serve with the hot chicken.