The spicy ingredients listed above give you a sweet hot sauce. If you want to reduce the spice level, remove or reduce the hot ingredients in this order: cayenne powder, chile peppers and finally reduce, but don't remove all the sriracha sauce.
Substitute dried Thai chiles for the cayenne peppers if desired.
You can also cook the steak in a wok. Heat 1 tablespoon of sesame oil in the wok over high heat. Stir-fry steak in batches until the sauce begins to darken and thicken, 2 to 3 minutes.