To find a powered parachute DPE (Designated Pilot Examiner) to perform a checkride (practical test) simply go to the FAA website listing and finding an examiner in your area.
Or, many times the instructor who recommends you for a checkride will suggest an examiner. This is the best situation if the recommending instructor and the DPE have worked together before.
The instructor typically will make certain you are prepared for your checkride because he will not want to recommend an applicant for a checkride and have that applicant fail.
FAA Sport Pilot DPE list
To find a list of FAA Sport Pilot Designated Pilot Examiners go to:
PPC Sport Pilot Designated Pilot Examiners