You clearly have a nest nearby, probably just outside the kitchen. You need to find the nest before you have a hope of ridding yourself of them. They nest underground and often come up between paving slabs or cracks in the patio. Go look! Subsequent eradication method depends on the location.
Lots of people seem to be having ant problems this year so you're not alone.
I had the same problem. Get ant traps at the store (I got mine at Krogers)and place 2 or 3 of them around the kitchen (if you have pets, make sure they can't get to them). I have 1 on my counter-top, 1 under the sink and 1 under my washer. It only took 2 days and I haven't had an ant since.