Most cans of tuna here (Uruguay) are not hockey-puck shaped - and soup doesn't come in cans either, but in Tetra-Paks, except for the rare Campbell's import.
Searching for images I came across this very relevant article on irregular can types:
When I look for tuna at the grocery store, I looked for the can shape, rather than the tuna section or tuna labels. If tomorrow I went to the grocery store, and all the cans of tuna were a different shape (or a different package) I would end up having to ask someone.
Searching for images I came across this very relevant article on irregular can types:
http://www.sommecan.com/nonround/irregularcanguide.html
Example of tuna cans in some spanish-speaking countries:
http://www.conservera.es/images/stories/virtuemart/product/3...