Flake the drained salmon into a bowl, removing any large skin pieces while leaving the soft edible bones if desired.
Fold in the eggs, cracker crumbs, onion, milk, mustard, pepper and salt just until the mixture holds together.
Shape 8 patties about 3/4 inch thick and refrigerate them for 15 minutes.
Heat 1/4 inch of oil in a skillet over medium heat and fry the patties in 2 batches for 3 to 4 minutes per side until deep golden and 145°F in the center.
Drain on a rack for 2 minutes and serve 2 patties per person with one lemon wedge.