In a large bowl, mix together tomato sauce, chili sauce, 1 cup sugar, and tapioca starch until well combined. Set aside.Advertisement
Heat oil in large saucepan over high heat. Add garlic, chili paste, and crab, stirring to combine. Add 2 cups water; cover and cook until crab is cooked through and liquid is reduced by half, about 5 minutes.
Add 2 cups of the tomato sauce mixture (reserving remaining for another use), bean paste, and remaining teaspoon sugar; stir to combine. Garnish with cilantro and serve immediately.