Heat the oven to 400°F.
In the bowl of a food processor with metal blade or in a blender, place the chopped dill, oil, walnuts, lime juice, garlic, mustard, 1/2 cup of cheese, salt and pepper.
Blanket; process, stopping once to scrape down side of bowl, until smooth.
If salmon has skin or bones, remove them; rinse the fillet and pat it dry with paper towel.
Cut the salmon into 24 cubes (1 inch).
On a cutting board, roll out 1 pie crust into a 12-inch round.
Cut in 4 rows by 3 rows to make 12 rectangles (4×3 inches).
Repeat with the remaining crust.
(Rectangles cut at the edge of the crust will have a rounded side.)
Place 1 level teaspoon dill pesto in center of each rectangle; top with 1 salmon cube.
Bring 4 corners of each rectangle over filling in center and pinch at top; pinch the corners, leaving small openings on the sides to release the steam.
(For rounded-sided rectangles, bring 3 points together at top, pinching to seal.)
On a large ungreased cookie sheet, place pastries 1 inch apart.
Bake for 20 to 25 minutes or until golden brown.
Place remaining pesto in a small resealable plastic bag for food storage.
Cut the small tip from a bottom corner of the bag; squeeze bag to drizzle pesto onto serving platter.
Place the pastries on a serving platter.
Sprinkle pastries with remaining cheese and garnish with dill sprigs.