This chicken char siu can be stored in the fridge for about 3 days. It is very useful as an ingredient for bento or toppings for fried rice and noodles.
The tomato sauce has a modest amount of salt so you can enjoy it all without worrying.
The time to cook the chicken in the microwave is a rough guide. If the meat looks kind of raw, microwave it a little at a time to extend the cooking time.