Cut flank steak into thin strips about 2 inches long.
In a large bowl, combine wine, sugar, soy sauce, ginger, pepper, cornstarch, and oil. Add meat strips and toss to coat. Let marinate for 30 minutes.
In a small bowl, combine the broth, cornstarch, soy sauce, sesame oil, sugar and ketchup; set aside.
Place wok over high heat and add 1/4 cup of oil (or less). Stir fry beef for 2 to 3 minutes. Remove with a slotted spoon and transfer to a large bowl. Add remaining 1/4 cup of oil and heat.
Add green onions and green pepper and stir fry for 1 minute. Add tomatoes and stir-fry for another minute. Add broth mixture and cook for 1 minute, or until it thickens slightly. Add beef and mix well.
Serve over jasmine rice.
Note: use oil portion at your discretion. Chinese cooking can be greasy but if you are watching your diet, use just enough oil to coat the meat, and prevent it from burning.