I don't know about where you are from, but from all my experience, those are not "SPIDER MITES". Spider mites actually have a web which if left unchecked will eventually cover the entire plant and they are very tiny and usually brownish to white in color.



I believe what you are seeing are " Leaf-footed bug babies".



Am I mistaken?

If I'm right, I don't have a better way of getting rid of them than hosing off, but I myself like to mash them to goo because they don't come back from that.