Combine chilli oil, soy sauce, tahini, five-spice, and black vinegar in a bowl or jug. Add the cold water gradually whilst stirring until you have a smooth soup consistency. Pop in the fridge for a few hours or until very cold.
When you’re ready to eat, cook the noodles according to package instructions and then drain and rinse in cold water to stop the cooking process. Toss the noodles in the sesame oil and set aside.
Cut the cucumber into matchsticks. Finely slice the spring onions. Roughly chop the peanuts.
Pour the soup broth into a bowl, top with the noodles, a couple of ice cubes, peanuts, cucumber and spring onions. Give it a good mix and get stuck in.
