Place the cauliflower and onion in a colander and cover with the salt. Leave for 24 hours before thoroughly rinsing off the salt. If the vegetables taste very salty after rinsing, leave them in a bowl of fresh water for 20 minutes before patting them dry.
Mix the cauliflower and onion with the cucumber. Bring the vinegars to the boil with the chilli, turn off the heat and leave for 20 m