We all have the same problem when buying chillies - they come in such bigs bags and we usually only need a whole one. So what to do with the rest?
Two choices here - firstly, freeze them whole or in halves. You can then either defrost them or slice them from frozen - you will be able to cut them super-thin too, perfect for garnishing.
Secondly, dice or slice them and cover with vinegar in a sterilised jar. Then use to instantly perk up salads, soups, stews and curries.