Tar excluding ._ files
Solution 1:
To suppress the creation of AppleDouble ._ files, use: --disable-copyfile
Example: tar --disable-copyfile -cf file.tar file
Solution 2:
In recent macOS versions --disable-copyfile option suggested in other answer might do nothing, but tar seems to honor COPYFILE_DISABLE environment variable. Use it like this:
COPYFILE_DISABLE=1 tar -cf file.tar file