There are a couple of things that people describe this way but in my experience mold mites, also called grain mites, are the most common. See this page about mold mites for a close-up drawing of a mold mite.
These mites feed on mold that grows on damp surfaces so are always associated with excess moisture in one way or another. Their presence in kitchens can indicate a leaky pipe or dishwasher. The mites don't bite or cause any harm but some people will experience an allergic reaction to large numbers of mites similar to dust mite allergy. In fact mold mites are related to dust mites.
The only treatment that is needed is to control the sources of moisture. Once the area dries out the mites will go away.
See the 'Bugs Website for additional information about household insect & mite pests.