I have structured data in a table, I can create it as content type in KC. Then what's the best way to import those data into Kentico Cloud?
At the moment, I think the best way is to write a simple tool utilizing the new Content Management API that will do that for you. Or wait until someone creates one.
Personally I've been creating json files that match our content items, and wrote a quick and dirty Groovy script to iterate through the files and post them via the Content Managment API... it would be rather trivial to have the script iterate through a CSV and build the JSON (probably easier than what I'm having to do, and building the JSON from JCR xml files from AEM in a separate Groovy script).
When I have some time to clean the script up a bit, I'd be more than happy to share it, with an example of how to iterate through CSVs and build JSON via groovy.