I came across this thread while looking for information on granular synthesis. My response is several years late. Did you ever get something that you were happy with? Your example link is no longer up.
I actually had a bit of success with synthesizing crickets. They aren't the same as cicadas, but maybe the strategy used will be a good starting point.
I employ a "carrier" sine wave of 4.5 KHz, and modulate its amplitude with a 66Hz sine. Another wave form (e.g., closer to square) for the amplitude modulation might work even better.
The cricket was done with Java and can be downloaded and heard here.
It is one of several tracks that can be mixed for a forest ambience. Most of the cues are recorded, but the cricket and the chirp were synthesized.