In medium bowl, combine beef, soy sauce, cornstarch, black pepper and garlic powder.

In large nonstick skillet over medium-high heat, heat 1 tablespoon oil. Add peppers, broccolini and shallots; cook 3 minutes, or until tender crisp. Transfer to clean bowl.

In same skillet over high heat, heat 1 tablespoon oil until shimmering. Add half of beef in single layer. Cook undisturbed 2 minutes, or until bottoms are browned. Stir. Cook 1 minute, or until outer surfaces are no longer pink. Transfer to bowl with vegetables. Repeat with remaining oil and beef. Return beef and vegetables to skillet over medium-high heat.

In small bowl, combine rice vinegar, sugar, sambal oelek, salt and ginger. Add mixture to pan. Cook 2 minutes, or until sauce is slightly thickened.