Process like Remon Koshi #1
Blood oranges can have thick zest, This is for a regular zester.
Take the chile and salt in a grinding bowl (suribashi) and process them into a chunky not-quite-paste.
Add the zest and process to a not-quite-paste
Use some (a scant teapoon to start) of the juice from the fruit to loosen it up a bit and improve the sour note, if desired.
Allow to fermet (koji) if desired.