Hot Dry Noodles (Re Gan Mian, 热干面)

3 tablespoons sesame paste or tahini

2 tablespoons sesame oil, plus 1 ½ teaspoons (divided)

1 ½ teaspoons dark soy sauce

1 tablespoon light soy sauce

½ teaspoon sugar

Salt,

240 g (about 8 oz.) fresh alkaline noodles

¼ cup chopped preserved mustard stems (zha cai, 榨菜), or to taste

¼ cup chopped pickled long beans (suan dou jiao, 酸豆角), or to taste

1 teaspoon minced garlic

Chili oil,

¼ cup chopped cilantro

2 scallions, chopped

½ teaspoon Chinese black vinegar