Wash the chillies under running cold water.
Poke a few small holes in the top of each chili to allow the pickle to penetrate them.
Add the water, vinegar, optional pickling spice, and sugar to a pot and slowly bring to a boil. Remove from the stove the moment it starts boiling.
Meanwhile, pack the chilies into the sterilized wide mouth jar.
Carefully pour the just boiled pickle mixture over the chilies, leaving no headspace.
Let it cool and remove trapped air bubbles by gently tapping the jar on the table.
Seal, label, and store in the refrigerator.
Use within four to six weeks. (Ours never last that long.)