**Prepare the Sauce:**
In a small bowl, whisk together soy sauce, sesame oil, oyster sauce (if using), and sugar. Set aside.
**Cook the Eggs:**
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium heat. Add the whisked eggs and cook, stirring gently, until set. Remove the eggs and set aside.
**Sauté Aromatics and Veggies:**
Add the remaining tablespoon of oil to the skillet. Sauté the diced onion for 2-3 minutes until softened. Add the minced garlic, cooking for an additional 30 seconds.
**Add the Veggies:**
Stir in the peas and carrots, cooking until heated through, about 2-3 minutes.
**Add the Rice:**
Increase the heat to medium-high. Add the cooked rice, breaking up any clumps with the back of the spatula. Stir-fry for 2-3 minutes until the rice is heated through.
**Combine:**
Pour the sauce over the rice and mix thoroughly to coat. Stir in the cooked eggs and green onions, mixing until evenly distributed.
**Serve:**
Remove from heat and serve immediately. Garnish with additional green onions if desired.