Fresh whole octopuses are available from the Auckland Fish Market but pre-frozen, pre-prepared octopus - the whole tentacles or the sliced meat - can be found at good Asian food stores.
Octopus can be tough if not tenderised before cooking. The traditional way to tenderise the meat is to hurl it against rocks; an easier method is to simmer it for an hour. After pre-cooking ...
If you wish to make this octopus recipe, you can then grill or sear in a cast iron pan after cooking and cleaning. There's no need to follow my sushi steps afterward!