For the marinade, in a small bowl, whisk together the soy sauce, rice vinegar and ginger. Pour the marinade into a sealable bag and add the cubed chicken. Seal and place in the refrigerator until ready to use.
To make the rice, add the water to a saucepan and place over medium-high heat. Cover and bring to a boil. Add the rice, reduce heat to low, and simmer until the water is absorbed and the rice is tender. Set aside and keep warm.
In a separate bowl, mix together the ingredients for the sauce. Set aside.
Before you begin, assemble and measure out all of the stir-fry ingredients. In a large wok, heat 1/2 tablespoon of the peanut oil over medium-high heat. Add carrots and red pepper and stir-fry for 2 to 3 minutes. Add the bok choy and pineapple and stir-fry 1 minute. Add onions and snow peas and stir-fry for another minute. Transfer mixture from the wok to a large bowl and set aside.
Return the wok to the burner. Add the remaining 1/2 tablespoon of peanut oil and the marinated chicken. Stir-fry about 3 minutes, or until the chicken is cooked through (internal temperature should be 165 F for 15 seconds). Add cooked vegetables and pineapple. Stir-fry for 1 minute more.
Stir the sauce mixture to make sure the cornstarch is completely dissolved. Add the sauce to the wok and bring to a boil. Cook until the sauce thickens and appears clear and shiny, about 1 minute.
To serve, add 1/2 cup of the brown rice to each of 4 warmed plates. Divide the chicken stir-fry evenly among the plates. Serve immediately.