Preheat oven to 350°F. Line a rimmed baking sheet with parchment paper. Add salmon cubes toDilled Dijon Sauce, and toss well until sauce is evenly distributed over each piece.
Arrange 1 salmon cube on the diagonal on each of the 8 prepared pastry squares. Working with one square at a time, fold each corner over the salmon neatly, cutting off excess dough as you go along. Turn over wrapped salmon and place seam-side down on the prepared baking sheet.Brush each pastry wrapped salmon neatly with egg wash. Bake uncovered for 30 minutes, until lightly browned.
While salmon is baking, place scallions in a medium bowl and pour boiling water over them to completely cover. Allow them to sit for 2 minutes. Remove from water, and pat dry. Tie each baked salmon pastry box with a softened scallion, and serve.