Prepare the rice by crumbling it with your fingers, breaking up the bigger lumps, and set aside in a bowl.

Heat a wok or a large, deep skillet over high heat. Add the oil, and when a bit of garlic sizzles at once, add the garlic and onion and toss well until shiny and fragrant, about 1 minute. Add the pork and cook, tossing often, until the onion begins to wilt and the meat is cooked through, about 2 minutes. Add the beaten egg, and toss well to scramble it once it begins to set.

Add the rice, fish sauce, sugar, and green onions and cook, tossing often, until the rice is tender and heated through.

Mound the rice on a serving platter and garnish with the cilantro, and if desired, the cucumber slices and wedges of lime to squeeze over each serving. Accompany with small bowls of fish sauce with chopped chilies, and serve hot or warm.