Season the lamb shanks liberally with salt and set aside long enough for the salt to dissolve, 15 minutes or up to 2 days. Dredge the shanks in flour (I put the flour and lamb in a plastic bag and shake).
In a Dutch oven or heavy ovenproof pot, add ¼ inch oil to the pot over high heat. When the oil is very hot, brown the floured shanks till they have a nice golden brown crust. Remove to a paper-towel-lined plate.
Heat your oven to 300˚F.
Pour the excess oil out of the pot. Wipe out the pot if the flour has burned and add a film of fresh oil and, over medium high heat, saute the onion, carrot and garlic till tender, five minutes or so.
Move the vegetables to the side of the pot and add the cumin, coriander, cayenne (if using), and ras-el-hanout or curry powder, and cinnamon. Stir to toast the spices then stir in the vegetables till they're coated with the spices.
Nestle the shanks into the pot. Add the tomatoes and red wine (it's best to crush the tomatoes in your hand as you add them to the pot). Cover the pot with a parchment lid (google ruhlman parchment lid for a video), or with the lid left slightly ajar, and place in the oven. Cook for 3 hours or until the shanks a completely tender.
Carefully remove the shanks from the pot. Blend the braising liquid with a hand blender (or in standing blender). Return the shanks to the pot with the sauce.
This can be served immediately or refrigerated for up to 5 days, then reheated and served.