Asian Eggplant Stir fry

Name: Asian Eggplant Stir fry
Ingredients: 1 pound Japanese eggplant cut into 1/4 medallions; 1 cup coarsely chopped green peppers; 1 cup coarsely chopped white onion; 1 chili pepper with 1/8 cut off of the bottom; 1/2 cup water; 2 tablespoons tamari; 1 tablespoon low-sodium soy sauce; 6 cloves garlic, minced; 1 tablespoon fresh ginger, minced; 3 tablespoons light brown sugar; 1 tablespoon cornstarch; 1 tablespoon peanut oil, evenly divided; 1 8 oz can drained chopped water chestnuts