Prep cucumbers. Wash well and trim off the blossom end to help keep pickles crisp. Slice into spears or rounds, or leave small cucumbers whole.
Make brine. Combine vinegar, water, salt, and sugar (if using) in a saucepan. Simmer, stirring until dissolved, then remove from heat.
Pack jar. Add garlic, dill, and any extra seasonings to the bottom, then pack cucumbers in tightly.
Pour brine. Cover cucumbers completely with hot brine, leaving ½ inch headspace.
Cool and refrigerate. Let cool to room temperature, then seal and refrigerate.
Wait. Best flavor after 24–48 hours; peak crunch and taste around 1 week.