Make the wet rub by pulsing the herbs, scallions, thyme, garlic, chili flakes, and the lemon zest and juice in a food processor until finely chopped. Mix in the olive oil. Slather both sides of skirt steak and let sit at room temperature for at least 30 minutes or up to 1 hour.
Preheat the grill or broiler to high. Using a paper towel, pat the steak dry and grill or broil until char appears and meat is cooked to medium rare, about 3-5 minutes per side. Let rest at least 5 minutes before slicing against the grain.