Preheat oven to 350°F. Line 2 large baking sheet pans with parchment paper.
Lay salami slices flat on sheet pans. Place pans in the oven and bake for 10 minutes, until pepperoni is browned on edges and crisp. Remove from oven and let cool.
In a small bowl, mix horseradish mustard and mayonnaise. Serve mustard dip with pepperoni chips.