The technique I used to accomplish this should be applicable to this situation:
Firstly, you want to make sure that your staticbody2D is actually an Area2D. This is because the Area2D node has the signal, "body_entered," which we will be using to detect collisions.
After creating an Area2D node, create a collisionshape2D that will serve as the "hitbox" of your wall, for your case it should cover the wall entirely I assume.
Connect the "body_entered" signal from Area2D to the script of your choosing.
func _on_Area2D_body_entered(body):
#Anything you want to happen before the wall is gone above queue_free()
queue_free()
To specify the kinematicbody2D, you can do the following:
func _on_Area2D_body_entered(body):
if body == "Missile":
queue_free()