Kinematic bodies are probably not the way to go here - as I understand it, their whole deal is being non-collided.
I would change the type of the enemy to
RigidBody2D - if you don't want it to rotate, you can change the
mode to "character"
Once you've got a rigid body, you can enable contact reporting (set
Contacts Reported to something greater than 0 and check the
Contact Monitoring box) and then hook up the
body_entered signal as pokumofu described. The enemy can check to see if it's collided with a player and let it know: something like
# in enemy script
if body.get_name() == "player":
Then in the player:
# in player script
# do whatever