Wash the peppers, shake off excess water, and pat dry. If your chilies are very spicy, it’s a good idea to remove some seeds before charring.
Put a metal rack over your stove grate (I just used the rack from my toaster oven!), and turn the heat on at medium-high. Char the peppers in batches over the open flame until the skin is just charred and wrinkly, turning often. Avoid overcooking them. The main goal is to char the skin.
Let sit at room temperature until cool enough to handle. For this next step, you can wear food grade gloves if your chilies are very spicy. Peel off the pepper skin. You can leave a little behind for a little extra charred flavor or get rid of it entirely.
With a mortar and pestle, smash the raw garlic, then add the roasted peppers along with the light soy sauce, rice vinegar, sesame oil, and sugar. Continue mashing until well-combined.
Peel and cut century eggs into smaller pieces. Add them to the mortar, and mix them in with the peppers. Salt to taste, and use a rubber spatula to mix everything well before serving.