We have a plethora of fruit flies in the kitchen. Probably because we have a plethora of fruit and veggies. At any rate, here's an easy way to get rid of them. Put some vinegar in a dish and add a couple drops of dish soap. The dish soap helps to drown
Here's the end result. Hard to see but after an evening there were a million of them floating in just one of our containers. After 24 hours, there were no more flies.
Side note, be SURE and eliminate their breeding areas. I had to wash and put all fruit/veggies in the fridge and flush out the kitchen drain with boiling water.