Preheat oven to 350 degrees F (175 degrees C). Grease 2 baking sheets.
Combine all-purpose flour, 4 1/2 tablespoons margarine, water, and confectioners' sugar in a large bowl; knead until a dough forms.
Combine remaining 4 1/2 tablespoons margarine and cake flour in a separate bowl; knead until a dough forms.
Wrap the cake flour dough around the all-purpose flour dough; roll out into a 8x16-inch sheet. Fold into 3 sections as you would an envelope. Roll into a log about 1-inch thick. Flatten to make a 4x31-inch strip; cut into 10 squares.
Mix barbeque sauce and barbeque pork together in a bowl.
Place 1 tablespoon of the mixture in the center of each square of dough. Brush edges of dough with egg yolk. Roll up dough, sealing the ends. Brush the top of each pastry with egg yolk; sprinkle sesame seeds on top. Transfer pastries to the prepared baking sheets.
Bake in the preheated oven until crisp and golden, about 25 minutes.