Are there websites where I can get "lightning frequency maps" in near-real time (worldwide)?
Absolutely: The Blitzortung project has near real-time data for most if not all of the world.

I've also never taken the time to research how lightning detectors exactly work, but it's likely similar... and you can read about the Blitzortung instrument here.

Windy.com also appears to now have lightning data over at least the largest part of the globe (perhaps using the Blitzortung source).  And though it's not for your region, GOES new satellites also have a lightning detector on them, which you can view at some data from on any of the GLM links on this page.