Sure, it's really simple.

Run the line through the eyestrap. tie a simple square knot in the very end of the line (just on the line itself). Then tie another simple square knot around the eyestrap. That's it. I wouldn't believe that it would be easy to undo, but I've helped David de-rig the boat twice now and both times it was extremely easy to remove both square knots even after sailing in some substantial breeze.