In a saucepan bring water to a boil. Add rice and stir. Reduce heat, cover and simmer for 20 minutes or until all the water is gone and the rice is fluffy.
Heat oil in a large wok or frypan. Add pork and onion and stir-fry until done and no pink is showing. Stir in tomatoes and steam until tomatoes are semi-soft. Remove from heat and stir in the cooked rice. Add the fish sauce and beaten egg and stir well; the egg will thicken the mixture. Then it is Kal Pot and ready to serve!