Known to have been used in China since the 5th century, pure sesame paste or sauce - S: 纯芝麻酱; T: 純芝麻醬 (chūn zhī ma jiàng) is made from dark toasted white sesame seeds and sesame oil.
Tahini and Chinese sesame paste are NOT interchangeable as tahina has a much lighter toast, if any. Chinese paste is thicker and much more strongly flavoured. One unwitting friend used it to make inedible, disgusting hummus.
Instead, it is added to noodle dishes, used as a dipping sauce for hotpots and incorporated into stir fries.
Black seed sesame paste is used in tang yuan, a CNY treat of glutinous rice balls filled with the paste and served in a syrupy soup.
White seed sesame paste (left) and black sesame seed paste (right).