Slice beef and marinate in soy sauce, corn starch, and pepper. Set aside and marinate for 10 minutes.
Heat oil on a wok or large pan on high. When oil becomes shimmery, add in ginger and saute 1 minute. Then add in marinted beef on high heat, moving beef around occasionally to evenly cook ~3-5 minutes. Set beef aside.
Add additional oil. When oil is shimmery, add in garlic and allow to become light brown. Then add in tomatoes and garlic chives. Allow tomatoes and garlic chives to slightly soften, after about 3 minutes of cooking.
Add cooked beef into the tomato and garlic chives to stir fry together. Add in oyster sauce, sugar, and a small drizzle of sesame oil.
Taste for seasoning and add soy sauce, oyster sauce, and sugar to taste.