Bring a pot of water to a boil and add salt. Add the rice to the boiling water and cook according to the package instructions.
Heat the oil in a large nonstick skillet over medium-high heat. When hot, add the chicken in one layer and season with the red pepper flakes and some salt and pepper. Cook until light brown, about 4 minutes. Flip the chicken, add the bell peppers, garlic, ginger and scallion whites and cook, stirring, for 2 minutes. Stir together the balsamic and brown sugar and add it to the skillet. Cook until the vinegar reduces a bit, about 2 minutes. Mix the cornstarch with 1/4 cup water and add it to the skillet. Cook until the sauce thickens, about 1 minute.
Remove the rice from the pot and drain. Cut open the bag(s) and serve up. Spoon some of the chicken over the rice and garnish with the sliced scallion greens.