Prepare the cucumbers: Wash the cucumbers thoroughly and slice into rounds or spears. Set aside.
Pack the jars: Sterilize 1–2 pint-sized mason jars. Pack the cucumber slices tightly, adding garlic cloves, mustard seeds, peppercorns, dill (if using), red pepper flakes (if using), and a grape leaf or black tea (if using). Leave ½ inch headspace.
Make the brine: In a saucepan, combine vinegar, water, salt, and sugar (if using). Bring to a simmer over medium heat, stirring until dissolved. Remove from heat and cool slightly (about 5 minutes).
Pour the brine: Carefully pour the warm brine over the cucumbers, ensuring they’re fully submerged. Leave ½ inch headspace.
Cool and refrigerate: Let jars cool to room temperature, then seal with lids. Refrigerate for at least 48 hours for optimal flavor.