Layer okra vertically in 2 Mason jars. Add a garlic clove to each jar.
Heat vinegar, water, salt, chilies, mustard seeds and peppercorns in a saucepan over medium-high heat. Bring to a boil and lower heat. Simmer a few minutes, until salt and sugar have dissolved. Pour hot liquid over the okra. Distribute liquid, chilies and spices evenly between the two jars. Secure lids tightly and refrigerate. Pickles will be ready to eat in about 24 hours and will keep in the refrigerator for about a month.