1. Stem the chilis and cull any that aren't up to standards.
  2. Put 'em down on a comal (flat steel plate) and blast 'em with a butane blowtorch (not too much, now). Turn 'em over and blast again. This blisters and chars the skins which can be rather tough otherwise.
  3. Toss 'em around under running water to rub off excess char.
  4. Run 'em with the knife blade in a food processor to chop up for faster cooking.
  5. Put 'em in an enameled pot with a good dash of olive oil and a bit of salt. Simmer 'em a while in enough rice vinegar to make a loose paste.
  6. Run with the knife blade in the food processor until smooth. Pack in a jar.
  7. Clean up.
It helps not to breath during this process, especially the clean-up part where you have to be present close to the action. I was still encountering little clouds of "hot" air here and there around the house for an hour after cleanup.