With hands, break rice until grains are separated and there are no more lumps. Set aside.
In a pan over medium heat, heat about 1 tablespoon oil. Add onions and garlic and cook until aromatic. Add tomatoes and cook, mashing regularly with the back of the spoon, until softened.
Add "ginisang" (sauteed) shrimp paste and cook for 1 to 2 minutes. Remove from pan and set aside. If using "Raw" shrimp paste, add the shrimp paste and cook, stirring occasionally, for about 3 to 5 minutes or until color darkens and browns. Add vinegar and sugar and allow to boil, without stirring, for about 1 to 2 minutes. Continue to cook, stirring occasionally, until most of the liquid is absorbed. Remove from pan and set aside.
Heat a wok or wide skillet over high heat until very hot. Add 1 tablespoon of oil and swirl to coat bottom of the skillet and heat oil until the bottom of pan appears to shimmer.
Add the rice and spread on entire cooking surface of pan for about 45 seconds or until grains start to sizzle and then toss to redistribute, breaking apart pieces with back of spoon. Spread rice on surface again for about 45 seconds and then toss to redistribute. Repeat a few times until rice is lightly toasted and heated through.
Add sauteed shrimp paste. Continue to cook, tossing gently to combine, for about 1 to 2 minutes until rice is coated with shrimp paste and heated through. Serve hot.