In a mixing bowl, combine the ground pork, fish sauce, soy sauce, brown sugar, garlic powder, black pepper, and sriracha (if using). Mix until well combined.
Divide the pork mixture into four equal portions and shape them into patties.
Preheat a grill or skillet over medium-high heat. Cook the patties for about 5-6 minutes on each side, or until they reach an internal temperature of 160°F.
While the burgers are cooking, toast the hamburger buns on the grill or in a toaster until golden brown.
Spread a layer of mayonnaise on the bottom half of each bun. Place a cooked pork patty on top, followed by a generous amount of pickled carrots and daikon, cucumber slices, jalapeño slices (if using), and fresh cilantro.
Top with the other half of the bun and serve immediately.