To prepare the pickles, begin by combining sliced cucumbers, water, and lime in a refrigerator-safe container. Allow the mixture to rest in the refrigerator for a full day.
After 24 hours, drain the cucumber mixture and rinse the cucumber slices thoroughly three times. Next, immerse the cucumber slices in clear water and add half a teaspoon of alum. Allow the cucumbers to soak in the water and alum mixture for three hours, then drain the mixture.
In a separate container, prepare a mixture using the remaining ingredients, excluding the food colouring. If needed, heat the mixture slightly to dissolve the sugar. Place the cucumbers in the mixture, ensuring they are fully submerged. Allow the cucumbers to soak in the mixture overnight.
The following day, add green food colouring as desired to achieve the desired colour. Boil the cucumber mixture for 35 minutes.
Transfer the pickles into jars, making sure to seal them tightly. Finally, process the jars in a water bath canner for 10 minutes (for pint jars).