1. Rinse the chicken under cool water and then place in a large bowl to marinate.
2. Whisk together the soy sauce, rice vinegar, toasted sesame oil and ginger. Reserve 2 tablespoons of marinade and then pour the remainder over the chicken. Cover and chill for at least 30 minutes to marinate.
3. Preheat oven to 425 degrees. Place the chicken on a foil-lined baking sheet, discarding any used marinade.
Bake for 7 minutes then flip and cook for another 7 minutes, or until cooked through.
4. Meanwhile, steam the broccoli until tender (about 10 minutes). Once it's cooked, remove to a medium mixing bowl and toss to coat with the reserved sauce/marinade.
5. Serve the chicken and broccoli over rice.