As it turns out, the answer is yes! Even though the wings are flat and can't generate much lift, I was able to get up to about 15ft of distance on a 10ft drop.

click to watch the video
Here's how I did it:
First, you're going to need 2 of the set, or at-least two copies of the sails and some common Technic pieces. This is because the sails in the set are two different sizes (and I wasn't able to get a two-wing design to balance anyway).

the plastic sail sheet
Then you just build a really minimal and light-weight frame, with adjustable wing angles. Here's how I built mine, using only the parts from two copies of the set (click the images to view them larger):

glider top

glider bottom
You'll notice how this frame isn't very sturdy. Since the wings can't really generate lift anyway, there's no advantage to being able to throw it like a wooden or foam glider, and a stronger frame would just be dead weight.
The most-important thing about this design is being able to adjust the angle of the wings. Here's roughly the pitch that gave me the best results.

adjustable wing pitch
I gotta say, I didn't have high hopes for this project going into it, but ultimately I was pleasantly surprised with the results!