Combine the rice and water in a saucepan over medium-high heat. Bring to a boil then reduce heat to low, cover and simmer for 20 minutes or until rice is tender.
In a small bowl, stir together the soy sauce, peanut butter, vinegar and cayenne pepper. Set aside.
Heat oil in a wok or frypan over high heat. Add chicken, garlic and ginger then cook stirring constantly until the chicken is golden on the outside; about 5 minutes.
Reduce heat to medium, and add spring onion, broccoli, peanuts and the peanut butter mixture. Cook, stirring frequently, for 5 minutes or until the broccoli is tender and chicken is cooked through. Serve over rice.