Coarsely pound the garlic, green chilies, cilantro, and cilantro roots together. Add sugar and salt, then taste and adjust as needed. Add water to thin the dipping sauce if it's too thick. Squeeze in the lime juice. The sauce should be spicy first, followed by sour and sweet flavors.

Wash and cut the vegetables. Remove the mackerel meat from the bones and set aside. You can either fry or grill the mackerel, whichever you prefer.

Soak the rice paper wrappers in water, then remove and set aside to soften.

Place a layer of romaine lettuce on top of the rice paper to help prevent tearing and keep the filling from falling out. Fold in the sides and roll tightly to secure the filling.