Preheat oven to 275 degrees. Season the pork generously in salt, black pepper, and cumin. Place the pork in a large casserole dish (about 9 x 12) and nestle the onion, orange, garlic, cinnamon sticks, and bay leaves between the pork. The ingredients should be snuggly fit into a single layer. Pour the oil over the pork and it should almost cover the pork. Cover tightly with foil and cook for 3 1/2 hours until tender.