Remove the thicker stems from the arugula and put it in the food processor. While the machine is turning add the oil slowly.
Put the oil away for about an hour at room temperature, add salt afterward to taste.
Chop the salmon filet and smoked salmon in cubes. Make 8 thin slices from the lemon and squeeze the rest. Mix both salmon types with lemon juice, creme fraiche and about 3/4 of the chives. Cover and keep refrigerated until you use it.
Put the form on a plate and fill with 1/8 of the salmon mixture. With the back of a spoon press it firmly. Remove the ring. Put a slice of lime on the salmon and some of the chives. Drip the arugula-oil around the salmon and serve.