Combine eggs and salt in medium bowl. Gradually add flour alternately with milk, beating with electric mixer or whisking until smooth. Beat or whisk in oil.
Cover and refrigerate batter for at least 30 minutes to allow flour to expand and air bubbles to collapse. Spray 8-inch (20 cm) non-stick skillet or crêpe pan with cooking spray. Heat over medium-high heat until water droplets sizzle when sprinkled into skillet. Stir batter. Pour about 3 tbsp (45 mL) batter into skillet all at once. Quickly tilt and rotate skillet to coat bottom with batter. (Batter should flow readily. If it has thickened during standing time, add about 2 tbsp (25 mL) milk to batter in bowl.) Cook until bottom of crêpe is slightly browned, about 45 seconds. Turn crêpe over. Cook for 15 to 30 seconds on second side. Transfer to plate. Repeat with remaining batter, adding more cooking spray to skillet if crêpes start to stick.
Combine sour cream and dill in small bowl. Spread about 1 tbsp (15 mL) mixture on one crêpe. Arrange afew pieces of salmon over top. Fold crêpe into quarters or roll up. Repeat with remaining crêpes.
Instead of sour cream and dill filling, use dill-flavoured spreadable cream cheese.
Any leftover crêpes can be stacked, layered with waxed paper, then wrapped well and frozen for up to 4 months.