Heat vegetable oil in a medium saucepan over medium heat. Cook and stir garlic and ginger in hot oil until fragrant, about 1 minute. Add hot water, peanut butter, and lemon juice to the saucepan; stir until smooth. Stir chili sauce, hoisin sauce, and soy sauce into the peanut butter mixture.
Reduce heat to low and cook sauce at a simmer until thickened, about 5 minutes. Add red pepper flakes; stir.
Spicy Thai Peanut Sauce · Dinner Match Lab | Dinner Match Lab