Heat a wok or large skillet over high heat and add the sesame oil.
Add the garlic and stir for about 30 seconds until fragrant.
Add the sliced onion and cook for 2 to 3 minutes until softened.
Stir in the carrots and green beans. Cook for another 3 to 4 minutes until they begin to soften.
Add the cooked protein and scrambled eggs. Toss everything together and let it heat through.
Add the cold cooked rice and break up any clumps. Stir-fry for about 4 to 5 minutes, mixing frequently so the rice heats evenly.
Drizzle in the soy sauce and season with salt and black pepper. Toss everything together until the rice is evenly coated.
Taste and adjust seasoning if needed. Serve immediately while hot.