Heat a heavy bottomed pan or casserole with the oil in it.
Once hot, add the duck legs and brown well on both sides.
Remove the legs and set aside.
Add the onions and garlic.
Saute until the onion is soft.
Add the spices and mix through.
Add the tinned tomatoes and lemon slices.
Season with salt and pepper.
Add the duck legs back to the pan.
Pour in enough stock to cover the meat.
Bring the sauce to a boil, lower the heat to a simmer, cover and cook on low heat for an hour or until the meat is quite tender and almost falling off the bone.
Check seasoning and add more salt/pepper as required.
Serve hot with rice, polenta or warm crusty bread.