Discalimer: I have a little bit experience with Rust, solid experience with Kotlin, no experience with Kotlin Native, but I have some thoughts 
I think the main difference is that you have much more control what the computer actually does in Rust. It is harder to learn and use Rust, but you can squeeze out the last bit of efficiency. Another difference I see is that Kotlin Native is relatively new and immature whereas Rust already has matured a bit (although it is also new compared to it’s main competitor C++). The Rust ecosystem is probably a lot bigger. Kotlin uses garbage collection at runtime whereas Rust checks memory management at compile time. Rust is cleaner in some aspects, because compatibility with the Java legacy (null, abstract class/interface with default methods) was not a design restriction. From a programmers point of view Rust is more functional and less object oriented, you can see this in error handling, pattern matching and the absence of null and classes.