Specifically remove files starting with ._ using terminal

find . -type f -name "._*" -print

This will find and display the names of all the files matching the filename globbing pattern ._* in the current directory, or in any of its subdirectories.

To remove them, change -print to -delete, or just add -delete to the end if you want to see what gets deleted.

The command to remove all files which starts with ._ is:

rm ._*

Before running rm command which will delete all files which match the pattern ._*, I'd suggest running the ls command to provide the list of all files which match the pattern:

ls -lsa ._*