Clean mason jars with warm soapy water and let them dry completely.
Wash cucumbers and cut into 4-inch spears. Peel garlic and leave whole.
Place the cucumbers in the mason jar first, packing them in tightly. Surround the cucumbers with equal amounts of garlic cloves and dill sprigs. Add more cucumbers until there is no space between the vegetables and the jar.
Add 2 teaspoons of mustard seeds and 2 teaspoons red pepper flakes to each jar.
In a saucepan, bring the vinegar, water, sugar, and salt to a roaring boil. Remove the mixture from the heat and divide the liquid equally between the two jars. Let cool to room temperature.
Once cool, add essential oils, seal the lid, and place it in the back of the fridge. After 2 days, sample a pickle from a jar. It should be crisp and slightly sour. You should be able to easily snap it in two clean pieces. If they are still kind of soggy, leave them be for another day or so before eating. Enjoy!