Make the sauce. Dissolve 1 tablespoon cornstarch in 1 water. Then mix with other sauce ingredients. Stir to mix. It's okay if it separates phase while you cook, you will stir it later. Set aside.
Cut tofu into small cubes, about 1/2 inch in width. (I usually cut the block through the middle once horizontally, and then cut to make a grid on the tofu)
Mince garlic and ginger. Alternatively combine in a food process and let it mince for you.
Cut scallions to separate the white root area from the green leaf area. Chop the roots small and mix with the minced garlic and ginger. Chop the green leaves and set aside for garnish at the end.
Heat oil in pot till hot (about 1 minute on high heat or 1.5 minutes on medium high)
Add the garlic, scallions, ginger and stir for 20 seconds.
Add hot chili bean sauce and stir fry for another 20 seconds.
Add the 1 block of cut tofu, and stir very gently for 10 seconds. Don't push the tofu too hard, or it may break.
Give the sauce a good stir, and add it to the tofu. Let the tofu boil in teh sauce until the sauce gets very thick. This took about 2-3 minutes for me.
Serve hot!