In a medium-sized pot, mix the vinegar, water, pickling spice, and salt. Bring to a boil over medium-high heat, which takes roughly 10-15 minutes. Remove from heat and set aside to cool.
Slice the cucumber into 1/4-inch-thick slices and thinly slice the green onions.
Pack the cucumbers into two 8.5-ounce jars with tight-fitting lids or hinged lids.
Add the sliced green onions, jalapeños, and garlic to the cooled pickling liquid and give it a stir. Then pour the liquid into the jars, covering the cucumbers and filling the jars to the top. Seal the jars tightly.
Place the jars in the refrigerator and let the cucumbers marinate for at least 24 hours. Enjoy your pickles cold.