Quick-pickled cukes give these burgers tart crunch. Panko and egg white hold the patties together. Use cilantro leaves on the burgers as you would lettuce for herby freshness.
Using the cilantro stems for the base of the sauce (instead of throwing them in the trash) is a flavorful way to stretch a buck or two. If you can't find skin-on boneless chicken thighs, purchase bone-in and bone them yourself or have the butcher do so.