Importing Photos and NOT including Metadata at the same time

Create a Metadata Preset with the fields that you want to strip out included and checked but left empty. Apply this preset on import with "Replace" selected.

You cannot remove EXIF data. It is permanently in the files. You can only change IPTC data.

Aperture does not allow to modify EXIF tags. You will need other tools for doing that. If you know hot to use the Terminal, you can modify EXIF tags with exiftool, see:

Modifying EXIF tags of Originals Using exiftool: camera, lens, gps

It will be safe to use as long as you run it and strip the exif data out BEFORE importing the files into Aperture. If you do it after you could cause problems with the Aperture library.

regards