Wide-field surveys conducted by the Herschel Space Observatory have discovered an exciting population of dusty star-forming galaxies (DSFGs) at z>2 that are gravitationally lensed by an intervening galaxy or group of galaxies along the line of sight. These systems are extremely useful probes of galaxy evolution because (1) they act as cosmic telescopes that increase the apparent brightness and size of the background source, facilitating follow-up observations; and (2) they provide an independent measurement of the mass of the foreground lens(es). I will present high spatial resolution SMA and ALMA imaging of lensed DSFGs discovered by Herschel and describe a novel technique to model each lens system in the visibility plane (as is appropriate for interferometers like ALMA and the SMA). I will summarize what we have learned about the nature of galaxy evolution based on these studies using both the lensed DSFGs and the lensing galaxies.