Cut beef across grain into thin slices 1/2"x2"
Combine Marinade ingredients, cover beef, and refrigerate for at least 15 minutes.
While beef is marinading prepare veggies:
Cut celery and onions lengthwise into 1 1/2" -2" strips
slice tomatoes into in eights, sprinkle with brown sugar set aside
Add sesame oil to preheated wok
add garlic, once aroma rises stir in beef until lightly browned - set aside
Allow wok to reheat, add oil if necessary.
Combine fresh ginger slices, celery, snow peas -stirfry for 30 seconds add tomatoes, cover - bring to boil.
Add cornstarch mixture (into middle of wok) stir quickly to thicken
return beef to wok, stir
season to taste