Drain the salmon, remove bones and pieces of skin, and place the salmon into a bowl. Flake the salmon apart with a fork. Stir in onion, lemon juice, horseradish, and salt until mixture is well combined.
Stir in smoked salmon cream cheese spread, a few spoonfuls at a time, until the spread is very well combined. Pack into a serving container, and sprinkle with parsley to serve.