You definitely want to steam your vital wheat gluten dough before searing the pieces in a pan. Steaming locks in that great seitan texture without soaking it in extra water, which makes getting a golden, browned crust so much easier later. A spoonful of all-purpose flour blended right into the dough helps keep the chew nice and tender rather than overly dense; just be sure to knead only as directed so you don't turn it tough.
Pan-fry the steamed bites until those edges get wonderfully crispy, then pull the pan off the heat before tossing them with your sweet-savory glaze. Saucing them away from direct heat protects all that hard-earned pan crust. Keep in mind that this whole dish relies on pure wheat gluten, so you can't make it gluten-free simply by subbing out the flour alone.