There is no way to do that out of the box if you run them using command line kotlin. Only manually (passing paths to jars to add them to classpath)
But projects like kscript handle this for you
https://github.com/holgerbrandl/kscript
Also, there is proposal from Kotlin team about improvement scripting support. Probably it will provide external dependencies management support out of the box. This proposal still in work tho.
https://github.com/Kotlin/KEEP/pull/77