Cook the pasta in a large saucepan of salted boiling water following packet directions or until al dente. Drain and return the pasta to the pan.
Meanwhile, heat 1 tablespoon oil in a large frying pan over medium-high heat. Cook the capers, stirring, for 1-2 minutes or until they ‘burst’. Use a slotted spoon to transfer to a plate.
Add the salmon to the pan and cook, turning occasionally, for 3-4 minutes or until golden. Transfer to the plate.
Heat the remaining 1 tablespoon oil in the frying pan over medium-high heat. Cook the onion, stirring often, for 5 minutes or until softened. Add the cream. Cook for 2 minutes or until the cream reduces slightly.
Stir the pasta, spinach, lemon juice and half the parsley into the cream mixture. Season. Cook for 1 minute or until heated through. Gently toss through the salmon. Sprinkle with capers and remaining parsley. Serve with lemon wedges, if using.