Split leek in half lengthwise. Rinse under cold water to remove any dirt, remove the white bottom end and peel the layers apart. Fill a large bowl with ice water.
Bring a large pot of water to a boil over high heat. Add the leeks to the boiling water and cook for about 20 seconds, remove and plunge into the ice water to cool. Remove leeks to a tray lined with a paper towel to dry. When dry cut each leek layer lengthwise in strips about 1/8-inch thick and reserve.
In a medium mixing bowl combine the flour, salt and pepper. In another small bowl whisk together the eggs and milk until well combined. Add the milk mixture to the dry mixture, whisking to prevent lumps, being careful not to overwork. In a small saute pan melt the butter until lightly browned and mix into the batter along with the chopped chives. Let batter rest while you make the filling.
In a medium mixing bowl combine all of the ingredients for the filling, folding salmon in last and mix until just combined.
Melt a small amount of the butter in a 10-inch nonstick skillet over medium heat. Add 2 ounces, about 1/4 cup, of the crepe batter to the hot skillet. Remove from the heat and tilt slightly to coat the entire pan evenly with batter. Return to the heat and cook until lightly browned on the bottom side, about 50 to 60 seconds. Using your fingertips or a rubber spatula, carefully turn the crepes over and cook on the second side for 10 to 15 seconds. Set the cooked crepe aside on a baking sheet to cool and repeat this process with the remaining batter. Should make 8 crepes.
When the crepes are cool lay out on a flat surface and with a spoon place some of the smoked salmon mixture in the center dividing evenly among the crepes. Pull the crepe together to form a little purse and tie the top of the crepe with one of the blanched leek strips. Serve 1 or 2 per person.