I got this ._ file name after extracting zip file on directory. In my case it was automatically created after unzipping. Here is how I delete that unwanted files.
On your mac terminal run the command:
I always wanted to delete this in linux way and you can still perform this on your mac terminal.
Step one: browse on the directory where the ._ file name using the command:
Step two: When you are in the directory that you want to delete all the files with name ._, just run the command:
find . -name '._*' -type f -delete
That how easy it is to delete ._ files on your mac