Place the rice and water in a saucepan and bring to a boil. Reduce heat to low, cover, and simmer until water is absorbed, about 45 minutes. Set aside to cool.
To make the dressing, whisk together the oil, lemon juice, soy sauce, ginger, and teriyaki sauce in a small bowl. Season with salt and pepper.
In a large bowl, mix together the cooked rice and chicken. Stir in celery, water chestnuts, mushrooms, green onion, and red pepper. Mix with the dressing to coat. Cover and refrigerate 8 hours or overnight. Toss gently before serving.