Blanch rhubarb in boiling water for 1 1/2 minutes. Drain and pat dry.
In medium bowl, combine almond cookie crumbs, brown sugar, cinnamon, orange zest and walnuts.
Place thawed pastry dough on floured surface. Lightly flour and roll to 12 x 15 inch rectangle.
Preheat oven to 375° F. Line a baking sheet with parchment paper.
Make a compact row of rhubarb pieces 2 inches from one long edge of the dough. Sprinkle rhubarb evenly with sugar mixture.
Starting at edge with rhubarb, roll up dough like a jelly roll. Turn seam side down and fold both ends under to seal.
Bake until golden brown, 40 to 50 minutes. Let stand several minutes, and then slice. Serve warm with vanilla ice cream.