In a medium bowl, combine the salmon, bread crumbs, mustard, and zest and season with salt and pepper. Stir in egg until just combined.
Form the salmon mixture into 8 to 10 cakes. Put the ground nuts on a plate. Gently press each side of the cake into the nuts. Refrigerate the cake for at least 30 minutes and up to 12 hours.
Heat the oil in a large non-stick skillet over medium heat. Working in batches, cook the cakes, turning once, until well-browned and cooked through, about 2 1/2 minutes per side. Transfer the cakes to a paper towel-lined plate to drain.
Divide the cakes among plates and serve with the lime wedges.