Start by slicing the beef into thin strips and marinate briefly with soy sauce to infuse flavor. Heat the wok over high heat and add a tablespoon of vegetable oil, swirling to coat the surface.
Once the oil is shimmering, add the beef strips in a single layer and sear without moving for about 1-2 minutes until they develop a nice brown crust. Toss and stir frequently, then remove the beef from the wok and set aside.
In the same wok, add a little more oil if necessary, then toss in the sliced red onion and minced garlic. Cook, stirring constantly, until the onion becomes translucent and fragrant, about 2 minutes.
Add the sliced tomatoes to the wok and cook for another minute, allowing them to soften slightly while maintaining some shape. You should see the mixture releasing a savory aroma.
Return the seared beef to the wok, stirring everything together so the flavors meld. Cook for another 2-3 minutes until everything is heated through and slightly caramelized at the edges.
Meanwhile, warm the fries either in a separate pan or oven until crispy and hot. Serve the stir-fry immediately, topped with the crispy fries or on the side, for a contrasting texture.
Plate the beef and vegetable mixture alongside the crispy fries, adjusting seasonings with salt and pepper if needed. Serve hot, garnished with extra herbs or a squeeze of lime if desired.
