I'm not much of a cook, my husband does all the cooking in our household, but I love cooking for my son. My mum used to make a salmon version of these patties or burgers for us as kids. It's a great recipe as all you need is a small tin of tuna or salmon in the pantry and a few odds and ends.
I like to use the tuna in springwater, rather than oil or brine, I just think it's gentler on little tummies. Then you need an egg, some bread crumbs (from a packet or just some stale bread) and some veges.
I drain the tuna and place in a bowl and quickly mash with a fork. Then add the egg and whatever veges you have lying around. It's a great way to hide veges if your child is fussy. I like to use frozen peas (a quick zap in some warm water first to thaw), beans cut into small pieces, grated sweet potato or pumpkin - but you can always use left over roast veges or whatever you have kicking around. Then I mix it all together and add the breadcrumbs a little at a time until the mixture combines.
Then with damp hands (stops the mixture sticking to you) I form it into little patties or burgers and cook in the frying pan until golden on both sides. I like to cook mine in a little butter as it gives them a nice texture and taste, but you could use a little olive oil too.
One little tiny tin of tuna and a couple of veges will make about 8 little patties, enough for his dinner, me to sneak a couple and leftovers for a yummy lunch or reheated for dinner the next night. It's a great recipe as all the ingredients are natural, you will probably already have them on hand and it's really cheap!