To make, for one drained six ounce can of salmon add: 1 egg, half a diced medium onion (shallots are even better), one slice of fresh bread w/o crust finely minced, a tablespoon of Dijon mustard, and some salt and pepper. Mix well and let that sit for a few minutes for the bread to absorb some moisture, and then form into three or four patties and pan fry in a thin film of oil until browned on each side. When making the patties, form into pucks somewhat firmly--there's no need to be super delicate. Also after flipping it over feel free to press down on the top of each patty with the turner to ensure good texture and contact with the pan.
For the sauce, it's something I've been putting on fish all winter. Greek yogurt (fat free is perfectly fine) thinned with lemon juice, a little mustard, salt, pepper, and some water if necessary to thin further. Usually the sauce gets loaded with chopped dill, which makes it appear a little less like . . . well, mayonnaise I guess but that's not really what I was thinking when I looked at the picture. Adding an herb or herbs (fennel tops work, parsley is fine, chives are great, so is tarragon) makes this go from very good to amazing and also makes it look very nice. We were just short of herbs, and even though this all purpose fish sauce is on the table pretty often, when I finally got around to grabbing the camera we were herbless.
Even if you don't like salmon, I can't recommend these patties enough. Seriously, these simple things give crab cakes a run for their money for a fraction of the price.