Slicing against the grain, cut them into 1 inch rings.
Clean the broccolini and put them into a large bowl with the onion rings.
Dress them with sesame oil, season with salt and pepper to taste, and set aside.
Preheat the grill on high heat.
After the steak is marinated, wipe off the marinade and season the steak with all 1½ tbsp (11 g) of black pepper on both sides and salt to taste. It is very important to grill the steak over high heat so there is a nice char and a quick sear, just like cooking in a wok. Skirt steak is very thin so it cooks really fast; each side will only take 90 seconds to 2 minutes for medium-rare.
Meanwhile, on the other side of the grill, char the red onion rings.
When both sides are charred, but the onion is still raw, place these into a salad bowl, cover with plastic wrap, and the carry-over heat will create steam to finish cooking them.
Lightly grill the broccolini so they are still green and crunchy.
Allow the skirt steak to rest for a couple of minutes before slicing.
Set them on top of the red onion rings and the grilled broccolini.
Finish with sea salt on the steak.
Serve with Black Pepper Sauce.
In a blender, combine ginger, green onion, garlic, soy sauce, oyster sauce and cooking oil and blend until smooth.
Pour this mixture into a shallow bowl and rub all over the steak.