In a food processor, whizz 100g salmon, then add the crème fraîche and cream cheese. Scoop into a bowl and fold in 1 tablespoon of lemon juice, a pinch of salt, pepper and the fennel, if using.
Very lightly oil 8 x 100ml moulds or ramekins and line with the remaining slices of smoked salmon, allowing them to hang over the edges. Spoon the pâté between the moulds or ramekins and fold the salmon over to cover. Cover with cling film and chill for 2 hours or overnight.
Mix the remaining lemon juice, the olive oil and sugar together. Divide the cucumber between plates. Turn the terrines out on the cucumber and garnish each with a dill sprig. Sprinkle the cucumber with the chopped dill and spoon over the dressing.
Recipe courtesy of Rachel Allen