We just got back from a little vacation in NH. We rented a condo to make life easier for us. It was a great place but there were tons of those little fruit flies or no see ums... or whatever they're called. I did a trick I learned awhile ago to help get rid of them. I put a small plate out with a little apple cider vinegar on it. I added a couple drops of dish soap and voila. They flocked to the vinegar and drowned.
Another option is waving your vacuum hose around like a mad woman. But I won't admit to doing that.
Apple cider vinegar.
A must have for every pantry.