Mix vinegar, salt, sugar, celery seed, black peppercorns, and cayenne pepper in a saucepan.
Boil, stirring constantly, until sugar is dissolved.
Remove from heat. Cool completely.
Slice cucumbers, peppers, and onion into a large glass mixing bowl, or stainless steel bowl.
Chop garlic and add this to the cucumber mixture.
Pour cooled brine mixture over the vegetables. Stir to combine.
Push veggies under liquid and weigh down with a heavy plate or bowl so veggies remain completely immersed.
Allow to rest, at room temperature, for 6 hours.
Transfer to large, sterilized canning jars. Cover tightly and refrigerate.
These will keep for 4 to 6 weeks in the refrigerator.
