In a saucepan, combine water, white vinegar, sugar, and salt. Bring to boil, stirring until sugar dissolves. Remove from heat and add sliced carrots and daikon radish. Let sit.

In a mixing bowl, combine ground beef, ground pork, green onions, fish sauce, and salt. Gently mix and form into four patties.

Heat skillet over medium heat. Cook patties for 8-10 minutes on each side until internal temperature is 160°F.

Toast the halved hamburger buns in the same skillet for 30-60 seconds until golden brown.

Spread Sriracha mayonnaise on the buns, then layer with a cooked patty, pickled veggies, cucumber, cilantro, and jalapeños. Top with the other half of the bun and serve.