Combine julienne vegetables and tarragon in a small bowl. Combine juices and oil in a second small bowl. Preheat the oven 425 degrees F.
Fold each piece parchment in half and then unfold. Set one piece of that parchment on a work surface. Set a piece of salmon in the centre, bottom half of the parchment. Season the fish with salt and pepper. Top salmon with quarter of the vegetables; drizzle with quarter of the juice/oil mixture. Fold the paper over the fish. Starting at one end, fold the edges of the paper together, overlapping them and pleating them to enclose. Twist the ends of the paper to seal. Set fish on a large baking sheet. Repeat with these steps with remaining paper, fish and flavourings. Bake 12 minutes, until the paper has browned and puffed and the contents are bubbling inside. Transfer fish to plates, cut open with scissors tableside, and enjoy.
Note: Julienne means to cut in thin strips that, in this case, are about 3” long.