Place pork and chopped tomatoes in a pot, pour water in pot until the pork is barely covered bring to a boil. If using tamarind place it on a muslin cloth and tie the ends. Bring to a boil then simmer for 30 minutes.
Add the taro then continue to simmer for 30 minutes.
Add the sinigang mix or if using tamarind extract all the juice by wringing the muslin cloth multiple times then remove once all juice is extracted.
Add green finger chillies, okra and string beans then cook for 5 minutes
While boiling add the kangkong leaves and cover, turn of the heat.
Season with freshly ground black pepper and fish sauce