Arrange the chicken pieces in a single layer in a roasting pan or large dish and season generously with salt and pepper.
In a small bowl, zest the lemons, then cut them in half and add the juice to the bowl.
Add the olive oil, crushed garlic, mild chili powder, and red pepper flakes to the lemon mixture and whisk until combined.
Brush the chicken pieces generously with the marinade so they are evenly coated, then pour any remaining marinade over the chicken.
Cover the dish tightly with plastic wrap and refrigerate for 2 hours; do not marinate longer to avoid the lemon juice breaking down the meat.
Preheat the oven to 375°F (190°C). Remove the plastic wrap and cover the pan tightly with foil, cutting a few small slits to vent.
Roast the chicken at 375°F for about 1 hour, until juices run clear and the internal temperature reaches 170°F (77°C).
Remove the foil, increase the oven to 425°F (220°C), and roast an additional 10 minutes or until the skin is nicely browned and crisp.
