Slow Cooker Chicken Lettuce Wraps

1 TBS sesame oil
3 lb ground chicken
1 ½ TBS ginger
¾ c hoisin sauce
3 TBS soy sauce
1 ½ TBS chili sauce with garlic
8 oz water chestnuts, chopped
2 head Bibb lettuce

Heat sesame oil in a large skillet and add ground chicken. Cook until no longer pink, breaking up into chunks. Add ginger root and cook for another minute. Drain meat and transfer to a slow cooker. Combine hoisin sauce, soy sauce and chili garlic sauce. Stir into meat. Cover and cook on high for 2 - 3 hours or low for 3 - 4 hours. Stir in water chestnuts. Keep on warm until ready to serve. Scoop spoonfuls of chicken mixture into each lettuce leaf and serve.  Serves 12