Wash the cucumbers thoroughly under cold water, trim both ends, and slice them into spears or rounds depending on your preferred pickle style.
Clean two glass jars with hot soapy water, rinse well, and place garlic slices, dill sprigs, peppercorns, and mustard seeds evenly between the jars.
Pack the cucumber pieces tightly into the jars, leaving enough space at the top so the brine can fully cover the vegetables.
Combine vinegar, water, salt, and sugar in a small saucepan, then warm the mixture gently until the salt and sugar dissolve completely.
Pour the warm brine over the cucumbers, making sure every piece is submerged beneath the liquid.
Allow the jars to cool at room temperature for a short time, then cover tightly and place them in the refrigerator.
Let the pickles rest for at least 24 hours before eating, although the flavor becomes stronger and more balanced after 48 hours.