In a small bowl, whisk together soy sauce, oyster sauce, and sesame oil; set aside.
Heat 1 tablespoon of oil in a wok or large skillet over high heat until shimmering.
Add the beef slices in a single layer and sear until browned, approximately 2 minutes. Remove beef and set aside.
Add remaining oil to the wok. Sauté garlic and ginger for 30 seconds until fragrant.
Add peas and carrots, stir-frying for 1-2 minutes.
Push vegetables to the side, pour in beaten eggs, and scramble until just set.
Add the chilled rice to the wok, breaking up any clumps with a spatula.
Return the beef to the wok. Pour the sauce mixture over the rice and toss continuously for 2-3 minutes until heated through and evenly coated.
Fold in sliced green onions and black pepper. Serve immediately.