Springtail,

6490.  Picture of tiny insects found in basement windowsill (taken in Toronto, Ontario Canada) mid- July. Toronto Ontario. Canada

Number 6490.  This appears to be a springtail, a primitive arthropod in the order Collembola, closely related to true insects. Ones like your specimen basically are harmless scavengers on bits of organic matter, but sometimes can be nuisance pests when they occur in numbers indoors. Moisture/humidity management is the best control.