Heat the sesame oil in a large saucepan, over medium heat. Add the ginger and garlic and saute until you can smell the aroma of the garlic, about 20 seconds. Add the broth to the saucepan with the water, vinegar, soy sauce, sugar and mushrooms. Cover and bring the liquid to a boil over high heat. Reduce to a simmer and cook over moderate heat until the mushrooms are tender, about 5 minutes. Add the bamboo shoots and chicken to the broth, bring the liquid back to a simmer and cook, over low heat until the chicken is cooked through. Add the peas and simmer 3 minutes longer or until heated through. Season to taste with salt and serve the hot sauce on the side if you wish.