Prepare the jars: Wash your jars and lids with hot, soapy water. Sterilize them in boiling water or run them through a dishwasher cycle.
Wash the cucumbers: Rinse the cucumbers thoroughly and trim both ends. You can leave them whole, slice them into spears, or cut them into coins.
Pack the jars: Place 1 clove of garlic, 2 sprigs of dill, ½ teaspoon mustard seeds, ½ teaspoon peppercorns, and a pinch of red pepper flakes (if using) into each jar. Pack the cucumbers snugly into the jars.
Make the brine: In a medium pot, combine water, vinegar, and kosher salt. Bring the mixture to a boil, then reduce the heat and simmer for 2 minutes.
Fill the jars: Pour the hot brine over the cucumbers, leaving about ½ inch of headspace. Make sure the cucumbers are fully submerged.
Seal and store: Wipe the jar rims clean, apply the lids, and tighten them. Let the jars cool to room temperature before storing them.
Wait and enjoy: Let the pickles sit for at least 48 hours to develop their flavor.
