Wash the cucumbers thoroughly and slice into spears or rounds; they should look crisp and bright green.
In a saucepan, combine water, vinegar, salt, and sugar; heat until the salt fully dissolves and the liquid is clear.
Place garlic, peppercorns, mustard seeds, and dill into a clean glass jar.
Pack the cucumber slices tightly into the jar without crushing them.
Pour the hot brine over the cucumbers until fully submerged; bubbles may rise to the surface.
Let the jar cool at room temperature until no longer warm to the touch.
Seal the jar and refrigerate for at least 24 hours; flavors will deepen and become more tangy.
