Drain the salmon very well and flake it into a large mixing bowl. If you prefer, remove any pieces of skin or bone.
Add the egg, almond flour, Parmesan cheese, mayonnaise, onions, chives, parsley, lemon juice, pepper, garlic powder, and salt. Use a fork to gently mix until just combined.
Do not overmix.
Shape the mixture into 6 equal patties, about ½-inch thick.
Place the patties on a plate and refrigerate for at least 20 minutes to help them firm up.
Heat the oil in a large skillet over medium-high heat.
Once the oil is shimmering, carefully add the patties in a single layer, working in batches if necessary. Pan-fry for 5-6 minutes on each side, until deeply golden brown and cooked through.
Transfer the cooked patties to a paper towel-lined plate.
Serve immediately, garnished with additional fresh chives, if desired.
Do not skip the chilling step. Refrigerating the patties before cooking is crucial for helping them hold their shape in the hot pan.