In a medium bowl, combine the brown sugar, green onions, ginger, cornstarch, garlic and salt with a whisk. Place pork in the bowl with the brown sugar mixture. Refrigerate for 2 hours. Meanwhile, cook rice according to package directions. Set aside.
Remove pork from refrigerator and bring to room temperature. In a wok on medium-high heat, add 2 teaspoons of peanut oil. Once oil is heated, add pork. Cook until pork has reached 155 F, about 7 minutes. While pork is cooking, heat a separate large saute pan to medium-high heat. Add the remaining 2 teaspoons of peanut oil to pan and saute the bok choy and carrots until tender, about 4 minutes. Serve with rice.