Add all of the marinade ingredients to a freezer bag and whisk to combine. Add steak and turn to coat. Cover and marinate 30 minutes at room temperature or refrigerate up to overnight (flank requires overnight).
When ready to cook, let beef sit at room temperature for 30 minutes. Heat some sesame oil over medium high heat in a large skillet.
Working in 4 batches, add meat (grabbing meat with tongs so excess marinade drips off) in a single layer and let sear 1-2 minutes. Flip and cook and addition 1-2 minutes or until browned but barely cooked through then add sesame seeds and stir to combine. Transfer to a plate and cover tightly with foil. Repeat.
Assemble Bowls: Add salad greens and rice to bowl. Top with beef, cucumbers and carrots, kimchi, etc.