Chop (or grate) onion and combine with lamb in a large bowl. Set aside.
Over medium-high heat, heat olive oil, and then add the spices: paprika, salt, chipotle, cumin, oregano, and pepper. Let spices blend for a few minutes.
Add spices to the meat mixture, mixing together thoroughly with hands.
Roll meat into roughly sausage-sized cylinders, then skewer and flatten slightly. Refrigerate kebabs for 30 mins (or freeze at this point)
Grill or broil kebabs, turning once until brown and charred on the outside and medium on the inside, approx. 4 mins per side. Serve with tzatziki sauce and naan.