Heat oil in a large fry pan. You might need two pans depending on how large yours is because you don’t want to crowd the Brussels sprouts.
Add Brussels sprouts and cook in an even, flat layer on high heat. Fry on one side then flip, about 3 minutes total. Watch out for flying oil poppers!
Meanwhile, whisk tamari, maple, and sriracha in a small bowl. Set aside.
Add sauce and toss until Brussels sprouts start to brown, another 1-2 minutes. Remove from heat when done.
Season with salt, pepper, sesame seeds, and green onion. Squeeze a splash of lime on top, if desired. Serve immediately.