Force Healing is what it sounds like, using The Force to heal a physical wound. It's not something that has existed in canon up until Kid Green looks like he's trying to do it. The power existed in Legends (the former Expanded Universe now rendered non-canon), but hasn't popped up in mainstream Star Wars.
What exactly is Kid Green?
Practically, this character is an absolutely adorable hybrid of CGI and puppet effects. Sure, it owes just as much to the Mogwai of Gremlins or the expressiveness of Stich from Lilo and Stitch, but the big-eyes-big-ears formula works and is cute. As to what the child actually is in the world of Star Wars, that's still a mystery.
We know for sure now that the baby is Force-sensitive, and since the other two members of its species that we've seen on screen (Yoda and Yaddle) both sat on the Jedi Council in the time of the Republic, it seems like a safe assumption that this species has an innate connection to The Force. It might be the only existing species to be connected to the Force in this way. There have been Force creatures, like the Force family on the planet Mortis in The Clone Wars (The Force given physical form and personalities), or the Bendu in Star Wars: Rebels (a Force being that was not light or dark), but the live-action series of movies got a little derailed in 1999 with midi-chlorians, and the films stopped trying to explain The Force in any detail.
The "Kid Green Clone" theory that was outlined last week still stands thanks to a lore shoutout I initially missed. In "Chapter 1," the white-suited gentleman played by Omid Abtahi is named Doctor Pershing. Thanks to some promotional photos, we can make out a patch on the good doctor's arm: