It really doesn't matter. I used fresh chili peppers (red ones from the supermarket), but dried whole chili peppers will work well, as well as chili flakes - use whatever you have on hand! Just keep in mind the level of heat you wan to add as everyone's personal preference is different. For example, the chilis I used were very spicy, so I only used 4-5 slices (about half of a pepper). You could try your chilis first to see how spicy they are to help you decide how much spice to add to the sauce.