Step 1

Whisk hoisin sauce, vinegar, soy sauce, hot sauce, sesame oil, grated ginger, garlic, brown sugar, salt, and pepper together in a large mixing bowl.

Step 2

Cut skirt steak crosswise into about 4 or 5 smaller pieces. Transfer steak into marinade and toss until all pieces are evenly coated. Cover with plastic wrap. Refrigerate; marinate at least 2 hours and up to 12 hours.

Step 3

Line a baking pan with paper towels. Transfer pieces of steak to the paper towels and mop off some of the marinade.

Step 4

Preheat an outdoor grill for high heat and lightly oil the grate.

Step 5

Transfer steak pieces to grill. Cook to medium rare or medium, 4 to 5 minutes per side. An instant-read thermometer inserted into the center should read between 130 and 135 degrees F (about 54 degrees C). Thinner pieces might finish earlier. Transfer steak to a warm plate. Let rest for a few minutes.

Step 6

Transfer steak to a warm serving platter and pour any accumulated juices over skirt steak. Sprinkle with sesame seeds and sliced green onions.