Peel the salmon off the skin and break it into smaller pieces between your fingers.
Mix the crème fraîche, mayonnaise, spring onions, pickled gherkins (if using), dill and lemon juice in a bowl – stir in the salmon and season to taste with salt and pepper.
Keep the salmon salad chilled until it is to be served – and top it with a little finely sliced spring onion just before serving.