Boil the tamarind in a pot with water, about 3 cups, adjust if necessary. Cook until the tamarind becomes tender.
Remove the tamarind from the pot and transfer to a bowl then mash it with a fork until the juices comes out.
Then put it again in the pot and stir. Strain the contents of the pot with a colander and pour it a another container to get the broth from the tamarind. Press it until the juices have been extracted.
In another pot boil the beef for about 5 minutes. Remove the liquid and scum then wash the meat.
Then replace the water by filling the pot just enough to cover the meat.
Boil until the meat is cooked and tender.
Add in the salt, onion, tomatoes and gabi. Boil until the gabi is cooked.
Then add in the string beans and radish. Simmer for about 3 minutes.
Pour the tamarind broth (or if you can't find tamarind, use sinigang mix), kangkong leaves and green chili.
Season with salt or fish sauce (patis) and serve hot.