Place pork ribs in a large pot. Pour water and bring to a rolling boil over high heat. Use a slotted spoon to skim off the scum that floats to the surface.
Add the red onion, tomatoes and fish sauce. Once it starts to boil again, cover the pot with the lid and lower the temperature to low. Let it simmer until pork becomes tender.
Add the taro and cover and simmer again for 5 minutes. (Optional)
Toss in the string beans and radish and let it cook for 2 minutes
Add the okra, eggplant, finger chili, and the kangkong stalks.
Add the tamarind paste and mix until dissolved. Season with salt if needed.
Before all the vegetables are done, toss in the kangkong leaves. Turn off the heat and let the vegetables finish cooking from the residual heat.
Serve in bowls with plain steamed rice and fish sauce with some of the finger chili squashed into it as a dip.
