MoltenVK is a standard implementation of Vulkan, and works like other implementations, using the same Vulkan C bindings. For iOS, you link to the MoltenVK framework within your project (typically Xcode).
We have not tested MoltenVK with VulkanSharp, but as long as you can access the standard Vulkan API through VulkanSharp, and have the ability to link to the MoltenVK iOS framework within your dev environment, it should work.
I’m getting closer to making MoltenVK work together with Xamarin/VulkanSharp. Unfortunately I’ve got problems with linking MoltenVK when compiling for the iPad simulator. Seems that the app is compiled for i386 when targeting the simulator and MoltenVK for iOS does not come with i386 compiled framework files. Any ideas about that? Is it possible to make MoltenVK work with the simulator?