Chinese sesame paste is made from toasted sesame seeds and is deep, dark and intense. It is used in sauces for cold dishes, including noodles and vegetables such as this cold cucumber dish, but is also sometimes found in dan dan noodles. Peanut butter and tahini taste quite different and are not great substitutions for zhi ma jiang. This well-known brand from Beijing does include a bit of peanut, which makes it less bitter and more deliciously nutty. Make sure to stir up the solids and oil before using. This can be difficult at first, so it is worth the effort to run it all through a food processor with a couple tablespoons toasted sesame oil to get a well-mixed, runnier paste for sauces.