1. In a mixing bowl, combine ground pork, fish sauce, soy sauce, minced garlic, ground coriander, ground cumin, sugar, chopped cilantro, and chili flakes.
2. Mix well until all ingredients are evenly distributed.
3. Form the mixture into 4 equal-sized patties.
4. Preheat the grill to medium-high heat.
5. Grill the patties for about 5 minutes on each side or until fully cooked.
6. Serve the burgers on buns with your favorite toppings.