Place onion, green peppers, tomatoes, drained pineapple chunks (reserve juice), tomatoes, bouillon cube, brown sugar, garlic powder, ginger and pepper. Top with water chestnuts then sliced sausage. Cook low for about 6 - 8 hours. (Note my crockpot only needs about 6 hours.)
Approximately 30 minutes prior to doneness, combine reserved pineapple juice and cornstarch; add to the crockpot and stir to combine. Replace the lid on the crockpot and turn the heat up to high for about the remaining 30 minutes of cooking time. Serve over rice.
Note: As an alternative method to thicken, drain juices from crockpot into a saucepan. Combine reserved pineapple juice and cornstarch. Add cornstarch mixture to the pan of juices and boil for about 2 minutes. (If tasting, refrain from redipping spoon. Enzymes in salvia break down the starch and will make watery.) Return the sauce to the crockpot and stir to glaze.