1. Preheat oven to 350 degrees Fahrenheit.
2. Lay out frozen puff pastry squares on your work surface.
3. Diagonally layer mustard, followed by cold cuts, on each pastry square.
4. Starting from one corner of dough, roll up tightly. Tightly secure the end and place deli roll seam-side down on a parchment-lined baking sheet. Repeat with remaining pastry squares.
5. Brush generously with duck sauce. Sprinkle sesame seeds over.
6. Bake for 20–25 minutes.