1/2tablespooncornstarch(mixed with 1 tablespoon water)
Marinate the meat with the cornstarch, the first teaspoon of oil, and salt. Set aside for one hour. Also, combine all the ingredients for the sauce base in a separate bowl. Set aside.
Add 1 tablespoon of oil to coat the wok and heat until just smoking. Spread the beef around the wok and sear for 1 minute until 80% done and remove from the wok. Set aside.
Heat another tablespoon of oil in the wok over medium heat. Add the ginger slices, and let caramelize for 10 seconds. Turn the heat up to high, and add the minced garlic, shallot, and the white portions of the scallion. Toss for 10 seconds.
Add the tomato wedges to the wok. Spread them around the wok in an even layer, and let sear for 15 seconds. Add the Shaoxing wine, and stir-fry the mixture for another 10 seconds. Now push everything to one side of the wok.
On the cleared space of the wok, add the sauce base. Stir until bubbling to meld the flavors together.
Now it's time to add the beef and any juices in the bowl to the wok. Stir–fry everything on high heat until mixed well and sizzling (about 20 seconds). Be sure not to overcook the tomatoes or they will disintegrate into the sauce!
Toss in the remainder of the scallions and add the cornstarch slurry a little at a time until the sauce is thickened to your liking. Let the sauce cook for 15 seconds after adding the last bit of the cornstarch slurry to ensure the starch is cooked. Plate and serve immediately on a big bed of rice!