tinned fish rule!! one of my favorite easy work lunches is just a couple slices of sourdough bread, some tinned fish in olive oil (usually sardines, herring, or mackerel) some greens (usually arugula) a squeeze of lemon, salt and pepper. There's all sorts of little additions that are great like capers, peppers, tomatoes, basically anything I have around.
I don't usually get the super fancy tins since they can be expensive, but now I kind of want to treat myself...
I'm honestly a little relieved to hear the opinions on canned octopus and squid. I always see them on the shelf and I feel curious but I have no confidence they would be good. From the description, it doesn't sound like my thing.