Cut jalapeños into thin slices, about ⅛" thick, and place in a resealable storage container.
Combine remaining ingredients in a small saucepan over low heat, stirring occasionally, until water just starts to boil. Remove from heat and pour over the jalapeño slices, submerging them in the water-vinegar mixture.
Cover, label & date, and refrigerate. If jalapeños aren't submerged, stir them around every time you get in the refrigerator for the first day or so.
Pickled jalapeños will keep in an air-tight container in the refrigerator for up to two months.
Enjoy these as a stand-alone snack or on sandwiches, burgers, salads, pizza, tacos, you name it!