In a large pot, bring the water to a boil over medium heat.
Add the pork pieces and let it simmer until the meat is tender, which usually takes about 30 minutes. Skim off any foam or impurities that float on top.
Once the meat is tender, add the onions and tomatoes to the pot. Let it simmer for another 5 minutes until the vegetables start to soften.
Add the tamarind juice or tamarind powder dissolved in water to the pot. Stir well and let it simmer for 5 minutes to infuse the flavors.
Add the radishes and string beans to the pot. Cook for about 3 minutes until the vegetables are slightly tender.
Finally, add the kangkong or spinach leaves and long green chili peppers to the pot. Cook for another 2 minutes until the greens are wilted.
Season with fish sauce or salt to taste. Adjust the seasoning according to your preference.
Serve the Pork Sinigang hot with steamed rice and enjoy!
