Rinse the cucumbers and jalapeños thoroughly, then slice the cucumbers into rounds or spears and cut the jalapeños into thin rings.
Divide garlic cloves, cilantro, and coriander seeds between clean glass jars to create the flavor base.
Fill each jar with cucumber slices and jalapeño pieces, arranging them tightly while leaving enough room for the liquid.
Heat vinegar, water, salt, and sugar together in a saucepan until the salt dissolves and the brine becomes clear.
Carefully pour the warm pickling liquid into the jars until all vegetables are completely covered.
Let the jars cool slightly before sealing them and transferring them to the refrigerator.
Wait at least 24 hours before serving so the cucumbers absorb the spicy, tangy flavors.