• Pat the ribs dry and season with the salt. Cut the ribs across the bone. Heat the oil in a large heavy pot over medium-high heat. Sear in batches, 3 to 4 minutes per side, until golden brown. Set aside.
• Lower the heat to medium. Add the onion and tomatoes and cook about 10 minutes, scraping up the browned bits, until soft and jammy.
• Return the pork and any juices to the pot. Add the fish sauce and enough water to cover by 1 inch. Bring to a boil and skim the foam. Reduce to a gentle simmer, cover, and cook 60 to 75 minutes, until tender.
• Meanwhile, prep the vegetables make the homemade tamarind paste (if using see below for instructions).
• When pork ribs are fork tender, add the taro and the long green chili (if using) and cook 10 minutes, until fork-tender. Add the daikon and cook 5 minutes. Then add the okra, green beans and eggplant and cook 10 minutes. Add the bok choy and cook 1 to 2 minutes, until just wilted.
• Stir in 3 tablespoons tamarind paste (or sinigang mix). Taste and add more until it is as sour as you like. Adjust with fish sauce. Serve hot with steamed rice.

Homemade tamarind paste (start while the pork simmers)

• Crack open the pods and pull out the flesh. Remove the shell and the tamarind veins. Place the flesh in a bowl and pour the boiling water over it. Let it soak for 30 minutes, until the flesh is soft and the water has cooled.
• Massage the pulp with your fingers to separate it from the seeds and fibers. Strain through a fine mesh sieve, pressing so all of the pulp goes through. Discard the seeds and fibers.