In a bowl, combine vinegar, 1 teaspoon oil and 1/4 teaspoon sugar.
Addcabbage, carrots and broccoli slaw; toss and set aside.In a second bowl, combine cilantro, mint, fish sauce, soysauce and remaining 1/2 tablespoon sugar.
Add tuna andscallions; mix until combined. Form tuna mixture into four3/4-inch-thick patties.
Place panko on a plate; coat eachpatty with crumbs. In a large nonstickskillet, heat remaining1 tablespoon oil over medium heat.Cook burgers, flipping once,until well browned, about4 minutes per side.
Place 1 burger onbottom of each bun;top with 1/4 of slawand other bun half.