How do you get rid of small ants in kitchen?

Deal with them outside. You have excessive ants due to numbers or they are being displaced by water/construction etc. If being displaced, make appropriate adjustment. If excessive, reduce their no. You can also bait areas inside they tend to use as "freeways"-anywhere pipes pass through walls. This will intercept the foragers & many times prevent them from looking any further. Monitor these routinely & replace when consumed.