They crawl around on the top of the soil when the plants are watered. From your description, I would say that you most likely have springtails living on the soil. Essentially, they live off of the decaying organic matter that is present in the dirt, and are more of a nuisance to the humans in the house than to the plants themselves. There is also a possibility that the insects could be thrips, however, and they can and will do damage to the plants. Thrips usually are only found on the underside of the leaves, so I don't think that they are your problem, but I can't eliminate that possibility.
Thrips rasp the leaves, and then suck the juices from the plant.
Evidence of thrips include small silverish streaks on the leaves where they have been scarred, as well as little black micro-poopies on the underside of the leaves. Both springtails and thrips can be controlled naturally if you wouldn't mind having a few lady bugs in the house.