Sizzlin' Spicy Szechuan Stir-Fry

divided

flank steak, thinly-sliced

medium white onion, peeled and thinly sliced

large red bell pepper, cored and thinly sliced

garlic, peeled and thinly sliced

batch Szechuan Sauce

optional toppings: thinly-sliced green onions, toasted sesame seeds, extra crushed red pepper flakes