I agree with DirtMechanic, that does look like a Lace Bug - immature, since there are no obvious wings showing. You need to get rid of them asap. They will hide under leaves and things, so you have to be very thorough with spraying. Be careful, because some types can bite, but they don't have any toxins. The upside is they tend to stick to one plant, so they don't spread very quickly. If you treat the plant and a few surrounding ones as soon as you see them, it will probably take care of the problem. We had them once on a cucumber plant.