Sprinkle flour over the pieces of beef and toss to evenly coat. Melt 2 tablespoons of veggie oil in a frying pan or wok over high heat. Working in small batches, add the beef pieces to the hot oil so that no two pieces are touching. Sear the beef on one side for about 2.5 minutes, or until it has a deep brown color, then flip it over to get the same texture on the other side. Once cooked and crispy- looking, transfer the cooked pieces to a separate bowl or plate. Continue with the rest of the beef pieces, adding more oil as needed.
Once the beef pieces are all cooked and set aside, add 1 tablespoon of veggie oil and the teaspoon of sesame oil to the same pan. Turn the heat down to medium and then add the garlic. Saute for about 2 minutes and then add the ginger and chili peppers. Saute for an additional two minutes, until fragrant, and then add the beef stock. Bring the sauce up to a simmer and use a spoon to stir while scraping any beef bits off the bottom of the pan.
Let the sauce simmer for about 15 minutes, or until it thickens enough to coat the back of a spoon. At this point, add the beef back into the pan. Add the green onions, stir, cover, and let the beef cook over medium heat for 3 minutes, or until the green onions are wilted. Turn off heat and serve with cauliflower rice.