This is the mandatory spicy accompaniment to all future taco eating. You can also take advantage of other hot chiles that pop at up this time of year—bright-red Fresnos, mild pasillas, or fiery habaneros. The pickles will keep at least four months in the refrigerator or canned in sealed jars for up to a year.
1. Sterilize 3 1-pt. canning jars and lids by boiling jars 10 minutes in large pot of water and simmering new lids in separate small saucepan 15 minutes. Leave jars and lids in simmering water until ready to use.
2. Combine vinegar, 2 cups water, salt, sugar, and oregano in large saucepan over high heat until boiling. Add carrots, jalapeños, and onion to vinegar mixture, and bring to a boil. Reduce heat to medium-low, cover, and simmer 12 to 15 minutes, or until carrots are crisp-tender.
3. Place 2 cloves garlic, 1 bay leaf, and 1 tsp. peppercorns in each jar. Divide vegetables evenly among jars, then cover with brine until completely submerged, leaving 1/4 to 1/2 inch headspace at top of jars. Discard or repurpose unused brine. Seal with lids, and process in boiling water bath 10 minutes. Alternately, invert sealed jars 15 minutes. Right jars, and check for proper seal (press on center of lid; it should be concave with no up-and-down movement). Cool. Let pickles marinate 12 hours before serving.