sesame paste, peanut butter (optional but it adds a nice sweet edge), soy sauce, freshly grinded garlic (as much as you'd like) mix with a little hot oil or hot noodle water (from boiling noodles). Chilli is optional too. That's the noodle sauce.
Mix in boiled noodles.
Serve with chilled sliced cucumbers or other crunchy veggies of choice (carrots, beansprouts etc.)
EDIT: Adding in a link to a legit recipe, but once you get your sauce base down, you can experiment with adding/removing components.