Season chicken with cumin, sage, salt, and pepper; place into a 9x13 inch glass baking dish skin-side up on top of the onions. Juice the lime and orange, and pour over the chicken. Cut the lime peel into quarters and place in the baking dish.
Loosely cover the dish with foil, and bake in preheated oven for 30 minutes. Remove the foil, reduce temperature to 350 degrees F (175 degrees C), and continue cooking until the skin is golden brown, and the chicken is no longer pink, 15 to 20 minutes.
