Measure 4 oz (125 g) green chilies, cut off and discard the seeds, and slice the chilies into pieces; place the sliced chilies in a small heatproof bowl.

Bring 1 cup water to a boil.

Carefully pour the 1 cup of boiling water over the chilies in the bowl and let them sit in the hot water for about 10 seconds.

Drain the chilies and discard the hot water.

To the same bowl with the drained chilies, add 1 cup Chinese rice vinegar, 1 teaspoon salt, and 1/2 teaspoon sugar. Stir until the salt and sugar are dissolved.

Transfer the chilies and pickling liquid into a small glass container or jar, cover, and refrigerate overnight.

The pickled green chilies will be ready to use the next day.