Neither approach is good if you are looking for work in the tech sector without an existing referral network.

I suggest that you;

• Ditch the cover letter
• Have a bulleted summary of your skill set that lists every skill and every technology you are comfortable with right on the first page
• In your experience, when listing your past jobs and positions, include list of every technology you worked with during your time there
• Customize your resume for every position by simply highlighting or emboldening every instance of the key technologies they are looking for in your resume

Note: Sometimes, when highlighting skills you might notice that your resume undersells your experience with that particular technology. Go ahead and edit it. This happens a lot and it is ok to view your resume as a living document that is constantly being revised. Don't just set it and forget it.