What are these bugs skittering about the kitchen sink?
Those are springtails, order Collembola. Looks like they are in the family Entomobryidae. They are completely harmless. They don't bite, or spread disease. They often find their way into potted plants in people's homes. I'm not surprised that they are in your sink. Their small size makes them subject to desiccation. 
https://en.wikipedia.org/wiki/Springtail https://en.wikipedia.org/wiki/Entomobryidae