Combine chile powder (or paprika) and oil in a small bowl with lime zest and juice, garlic, coriander, cumin, oregano, salt, pepper and cinnamon to form a wet paste.
*Using kitchen shears, cut the chicken down one side of the backbone, through the ribs. Make an identical cut on the opposite side to remove the backbone completely; discard (or reserve it for stock). Place the chicken cut-side down and flatten with the heel of your hand. Generously smear the spice rub under and over the skin and on the interior of the bird. Place in a glass baking dish . Cover with plastic wrap and refrigerate overnight or up to 24 hours.
Preheat half the grill to medium-high (or build a medium-high heat fire on one side of a charcoal grill); leave the other half unheated. Have a squirt bottle of water ready by the grill.
Leave the spice rub on the chicken. Place the chicken skin-side down over the heat and grill until the skin begins to color and char marks form, about 5 minutes. Flip over and grill 5 minutes more. Move the chicken to the unheated side. Close the lid and cook, making sure the chicken is flat against the grate, until an instant-read thermometer inserted into the thickest part of a thigh without touching bone registers 165°F, 30 to 40 minutes. Transfer to a platter and let rest for 5 to 10 minutes before carving.
*You can ask your butcher to do this for you