Preheat a barbecue or chargrill pan with a lid to high heat.
Combine gochujang, soy sauce, garlic and 1 tbs sesame oil in a large bowl. Add steak and toss until well coated, then thread onto 12 skewers.
Barbecue skewers with the lid closed for 1-2 minutes each side until charred and just cooked through. Rest, loosely covered with foil, for 5 minutes.
Meanwhile, barbecue broccolini, turning occasionally, for 3-4 minutes or until charred. Transfer to a large heatproof bowl and immediately add sesame seeds, lime juice and remaining 1 tbs sesame oil, tossing well to combine. Season to taste.
Serve skewers with broccolini, kimchi and lime halves alongside.
