Sprinkling vegetables with water is a common technique to prolong the postharvest life of these perishables (commodities which deteriorates readily). Technically, this is a form of evaporative cooling technique. It prolongs the shelf-life of vegetables through the applied concept of evaporation as a means of heat dissipation. Heat generated by the produce (i.e. vegetables) through respiration (plus heat within the microenvironment) will vaporize the sprinkled water. One should remember that there is the so called latent heat of vaporization, which is equivalent to 539 cal/g of water. As water evaporates, the heat load in the produce is reduced hence deteriorative changes associated with high temperature is regulated.
Similarly, evaporation of the sprinkled water will also increase the relative humidity within the microenvironment of the produce. With high RH, transpiration rate will decrease, hence wilting and weight loss for most vegetables can be controlled to some extent through this simple postharvest technique.
The cool feeling after a shower is also analogous to this technique. Heat load of the body is somehow dissipated, making us more comfortable.
Hope this helps.
Lessons in postharvest science