Cut beef with the grain into 2 inch strips.
Cut again across the grain for ¼ inch slices.
Stack the slices and cut across the grain into 2 inch long matchsticks.
Heat a wok over high heat.
Add 1 tbsp oil, add carrots, celery, and chilies.
Stir-fry 1 minute until the vegetables absorbed the oil.
Transfer to a plate.
Add the remaining oil and add the beef.
Allow to cook 1 minute and sear.
Then stir-fry 1 minute until beef releases juices.
Continue 2-3 minutes.
Reduce heat to medium and stir-fry 3 minutes.
Beef is browned and all the liquid is gone.
Add the soy sauce and stir-fry 30 seconds.
Add ginger and garlic.
When fragrant, add the vegetable mixture and stir-fry about 30 seconds.
Add the sesame oil and scallions.
Sprinkle on the salt and pepper.