Based on the information you've provided, you don't qualify for an open work permit.
Assuming you are American, if you are able to secure a full time job offer from an employer in Canada for an occupation that falls on the NAFTA list, then you can obtain a closed work permit (tied to that specific employer) without the employer also needing to obtain an approved LMIA. Otherwise the employer needs to obtain an approved LMIA and give you the job offer in order for you to qualify for the closed work permit.
I'm assuming you must have been looking at the post graduate open work permits. If so, those are only available to those who have studied in Canada and therefore not available to you.