Did a quick search for padded clips, and couldn't find the exact clips in your pic. However, I did find these other similar things. Maybe something will help.

Covers for snap clips, with instructions on how to attach to your own clips. If you're crafty, you could probably use a similar procedure with duckbill clips.

Pages selling duckbill clips suggest using grosgrain ribbon the same width as your clip for an inside lining. Apply with hot glue.
48pc Silver Single Prong 1.8" 45mm Hair Clip (L97)

Also, here is an Etsy listing for a duckbill clip lined with ribbon. Looks like it was simply hot glued around the handle bit and over and around the top part of the clip that would show when wearing:
Hair Clips Barrettes Heart Hair Clips Valentines by BabySmooches
CG since 11/2011
2c /3a F /Mii, low porosity

Autumn Products /Routine:
Clarifying: Herbal Essences Tealightfully Clean, Suave Professional Deep Clean Peppermint
Low Poo: Renpure Luxurious Argan Oil
Co-washes: VO5 Kiwi Lime Squeeze or Strawberries & Cream
Tresemme Expert Selection Perfectly (un)Done, Cure Care, VO5 KLS
LI (if needed):
Tresemme Perfectly (un)Done, VO5 KLS, Cure Care
Stylers: FSG, L'Oreal Clean gel, Tresemme Flawless Curls Bouncy Curls, LALSG, HETT, AIF
PT: IAGirl's as needed