Pound the steaks with a meat tenderizer gently until about 1.5 centimetres thick (approximately half an inch).
Slice the steaks lengthwise into long strips about 2.5-3 centimetres wide (about 1.5 inches).
Thread the steak strips onto metal or wooden skewers (about 2-3 strips per skewer, to make 6 skewers). Set aside.
In a large, shallow baking dish or container combine the onion, soy sauce, brown sugar, sesame seeds, sesame oil, garlic, ginger, sriracha, honey, and salt and pepper. Whisk until well combined.
Place the beef skewers in the marinade and turn the skewers in the marinade until well coated.
Cover with plastic wrap or a lid and refrigerate for two hours or overnight.
When ready to grill, place the beef skewers on a hot grill or griddle (outdoors or indoors) for no more than 5 minutes per side (it usually takes 5 minutes for the first side and then 3-4 minutes for the second side.
Remove from the grill or griddle and let rest under foil for 5 minutes before serving.