Wrap beef in plastic wrap and freeze until firm, about 1 hour.
Cut frozen beef at an angle into very thin slices.
Combine soy sauce, cooking wine, white sugar, ginger, garlic, and brown sugar in a large bowl. Mix in beef slices. Stir in kiwi pulp, onion, and spring onions. Cover bowl with plastic wrap; let beef marinate in the refrigerator, about 2 hours.
Stir sesame oil into marinade. Continue marinating beef in the refrigerator, 8 hours to overnight.
Heat vegetable oil in a wok or large skillet over medium-high heat. Pour in beef and marinade; cook and stir until beef is cooked through and browned, about 5 minutes.