Combine the soy sauce, black pepper, brown sugar, ginger and garlic to create the marinade.
Add the steak to the marinade and refrigerate for at least one hour and up to four.
Prepare your grill for direct high heat cooking.
Remove the steak from the marinade and place on the grill.
Flip the steak frequently to prevent burning and cook to an internal temperature of 130F. About 7-10 minutes. Remove the steak from the grill and allow to rest.
While the steak is resting slice the onions and cut the bell bell peppers into strips (discard seeds).
Sear the vegetables over high heat in a wok or cast iron skillet until tender. Stir frequently to prevent burning.
Slice the steak thinly, AGAINST the grain.
Serve the sliced steak, onions and peppers on corn tortillas with choice of salsa and/or sour cream.