Step 1

Prepare a grill for high indirect heat (for a gas grill, leave one or two burners off; for a charcoal grill, bank coals on one side); oil grate. Using a Microplane, finely grate lemongrass, chile (seeds and all!), garlic, and ginger into a medium bowl. (Alternatively, you can chop very finely, then mash to a paste using the side of your knife.) Add brown sugar, oil, fish sauce, and soy sauce and mix well.

Step 2

Season chicken with salt and add to bowl. Turn as needed to coat completely. Let sit at least 10 minutes and up to 2 hours. (If marinating longer, wait to fire up the grill.)

Step 3

Grill chicken over hottest part of grill, moving to cooler zone as needed if browning too fast, until well browned, about 5 minutes per side. Transfer to a cutting board and let rest 10 minutes before slicing.

Step 4

Transfer chicken to a platter and top with scallions and cilantro and sprinkle with sesame seeds. Serve with lime wedges for squeezing over.