Here's one of my favorite splash-dunk/spin-dry videos. It was taken at Cranberry Lake in Anacortes, WA.
The dragonfly in this video, most probably a male Paddle-tailed Darner, makes two nice splash-dunks. It then takes a long, smooth glide toward the water as if it might dunk again. At the last moment it changes its mind (apparently) and decides to head upward for a spin-dry. The resulting spin sheds a large number of water droplets.
Check out the post "How Slow Is Slow" to get a feeling for how slowed down this video really is.
Also, recall the following overview that gives a good idea of what's going on in splash-dunk/spin-dry behavior: