There are plenty of palaeoart examples of Rhamphorhynchus skim-feeding in the style of the extant tern-like bird, Rynchops. It's understandable - after all, Rhamphorhynchus is a seagoing pterosaur with a mouthful of forward-pointing teeth, occasionally preserved with the remains of its fishy meals within it. Factor that stuff together, and it's easy to imagine Rhamphorhynchus zipping along just above the surface of some shallow Jurassic sea, thrusting forward with its mandible slicing the water's surface, and snatching morsels of food as it finds them.
Humphries and Chums' 'Just Say No!' Campaign
In a 2007 paper investigating the possibilities of pterosaurs engaging in skim-feeding, Humphries et al found few adaptations towards this method of prey-capture, with the skull lacking the types of reinforcement seen in Rynchops. Read the paper here. Despite the refutation of the idea, it's a persistent one in palaeoart, probably in part because it makes for attractive images. Thanks to Humphries et al, this is probably as close as I dare get to showing a rhamph skimming:
|Rhamphorhynchus experiments with skim-feeding, remembers why it doesn't. (Copyright © 2015 Gareth Monger)|
Humphries S, Bonser RHC, Witton MP, Martill DM (2007) Did Pterosaurs Feed by Skimming? Physical Modelling and Anatomical Evaluation of an Unusual Feeding Method. PLoS Biol 5(8): e204. doi:10.1371/journal.pbio.0050204