Thinly slice meat across the grain and lay in a shallow glass baking dish. Pour over marinade and toss to evenly coat.
Cover and refrigerate for at least 30 minutes or until the next day, turning occasionally.
Place a wok or heavy nonstick skillet over medium-high heat. Add oil and when wok is hot enough to make a drop of water sizzle, add onions and peppers to the pan. Stir-fry for 4 to 5 minutes, until vegetables are tender.
Raise heat to high. Add meat and marinade to the wok and stir-fry until meat is lightly browned, about 4 to 5 minutes.
To serve, evenly distribute the meat and vegetables between the tortillas. Add hot sauce and yogurt to taste. Roll up tortillas to enclose filling..