Rinse the kangkong well to remove grits. Cut two inches off the lower end and discard.
Cut each stalk into three portions. Save the top leafy portion for another dish. Cut the middle and lower portion into one-inch lengths.
Peel the onion, halve and slice as finely as you can.
Thinly slice the chilies.
Mince the garlic.
Heat the cooking oil in a frying pan. Saute the onion, chilies and garlic until fragrant. Toss in the kangkong. Season with patis. Stir fry for about two minutes or just until the kangkong stalks are done.
Cover the bottom of a shallow bowl with the cooked kangkong. Top with the sliced roast pork belly. Serve hot with rice.