Place five garlic clove halves and five dill heads in each of three hot 1-quart jars. Pack cucumbers into jars to within 1/2 in. of the top., In a large saucepan, bring water, vinegar, salt and pepper flakes to a boil. Carefully ladle hot liquid over cucumbers, leaving 1/2-in. headspace. Add remaining five garlic clove halves to each jar. Remove air bubbles and adjust headspace, if necessary, by adding hot mixture. Wipe rims. Center lids on jars; screw on bands until fingertip tight. , Place jars into canner with simmering water, ensuring that they are completely covered with water. Bring to a boil; process for 15 minutes. Remove jars and cool.