Peel and slice your garlic cloves in half, lengthwise. Fill your quart sized glass jar with the garlic cloves, dill, coriander seeds, mustard seeds, crush red pepper flakes, and black peppercorns.
In a saucepan, combine your apple cider vinegar, water, salt and sugar and heat your pickling liquid over medium heat. Bring to a boil just until the sugar and salt dissolve, then remove from heat to cool slightly.
Using a mandolin or a sharp knife, slice your cucumbers lengthwise into 1/4 inch slices. You can sliced in rounds or lengthwise for a sandwich-style pickle.
Stuff the pickle jar with your cucumbers then pour the cooled brine over them.
Twist on the lid and chill in the refrigerator for at least 24 hours before serving. These will keep in your fridge for up to a month, though I’m pretty sure they won’t last that long—they’re that good.