Mix togethger the strawberries, onions and lemon juice and lemon juice and pour over the salmon. Leave to marinade for 30 mins. Then take the salmon strips out of the marinade and fry in the olive oil for several mins, turning them as they cook. Add the prawns and mushrooms and stir in the marinade with the strawberries. Simmer for a few more mins to allow prawns to cook and then serve with the parsley scattered on top.