Most cans of corned beef come with keys locked onto their sides so you can open them without an external can opener. Start by lifting the little metal clip to remove the key.
Then, flip the key around, pop it over that clip, and twist it slowly to gradually wind up a strip of metal that cuts off the base of the can, creating a lid you can pop open.
Once done, give the tin a little shake. Your canned corned beef should slide out in one chunk, allowing you to cut it into neat slices for integration into a dish.