In a bowl, combine the sliced beef, cornstarch, baking soda and salt. Mix well and let sit for 15 minutes.
Heat the vegetable oil in a large skillet or wok over high heat.
Working in batches, fry the beef for 2-3 minutes until crispy. Transfer to a paper towel-lined plate.
Reduce the heat to medium and add the garlic, ginger and chili. Cook for 1 minute until fragrant.
Add the soy sauce, rice vinegar, brown sugar and sesame oil. Stir to combine.
Return the crispy beef to the pan and toss to coat in the sauce.
Garnish with the sliced green onions and serve immediately.
