Transfer the soaked chillis along with the water to a wok or saucepan.
Bring the water to a boil.
Cover the pan with a lid. Cook the chillis in the water for about 5-10 minutes over low to medium heat.
This will make them soft.
Take the pan off the heat. Allow the soften red chillis to rest in the hot water for another 5-10 minutes.
Using a slotted spoon, fish out the red chillis into a blender jar. Add about ¼ cup water if need be. Use the water in which the chillis were boiled.
Process the red chillis to a paste. Can make it completely smooth or leave it a bit chunky. I left mine a bit chunky.
Heat the oil in a wok or pan over medium heat. Use the right amount of oil. This helps to preserve the sauce and also the chilli oil is useful for drizzling over soups.
Add the finely chopped garlic. Stir fry for 1-2 minutes.
Add the finely chopped ginger. Stir fry till the mixture turns light brown in colour. You will find that as the garlic and ginger get cooked, more oil will be seen.
Add the chilli paste. Cook the mixture till the water evaporates and the sauce becomes thick. Again cook it well so that it does not get spoiled quickly.
When the sauce is properly cooked you will not see water bubbles and oil will appear on the sides.
Add salt, sugar, soy sauce, sichuan pepper and tomato sauce. Mix well.
When the sauce cools down a bit, store it in an airtight jar.