This shows how to send messages to a connected Tessel over USB and how to log messages that the Tessel writes to console.log().
You'll need to do a
tessel push tessel-code.js to push the script to the Tessel first as it seems you can only have one connection at a time (unless there's another way I'm not aware of).
node host-code.js to send the message to Tessel. You should see Tessel log back the message it received.