Bluetooth Low Energy was introduced with Bluetooth 4.0, so any device with BT 4.x should be able to communicate with a BLE device. However, BLE is not backwards compatible with previous versions of Bluetooth (a BT 3.0 device is not going to be able to communicate with a BLE device). If you are able to detect a KW40Z with your computer, it most likely has BT 4.0 or newer. The VAR-SOM-SOLO/DUAL is a custom board not made by NXP, but according to its specifications, it has BT 4.0, so it should be able to communicate with the KW40Z. For support concerning the VAR-SOM-SOLO/DUAL you would have to contact its vendor directly.
If both your devices have BT 4.x, having them communicate with KW40Z has to do with the applications running in both the KW40Z and the device you want to connect to (either the PC or the VAR-SOM-SOLO/DUAL). If you want to use the KW40Z as a server, make sure it is advertising, so that other devices are aware of its presence. And in your client, make sure that it is scanning for clients with the set of services included in your KW40Z. Whether you can detect and connect to the KW40Z depends entirely on your application.
You can try several of the included examples in the KW40Z Connectivity Software. Once you have downloaded and installed the software shown in the previous link, you can program the board with any of the BLE examples available. The HID device demo should work with any PC or Android device with BT 4.x, without the need for additional software.
You can find the HID device demo in the following directory: <KW40Z_connSw_install_dir>\ConnSw\examples\bluetooth\hid_device\frdmkw40z\bare_metal\build\iar
You can find more information on how the demo applications work in the Demo Applications User's Guide. You can find that guide in the following directory: <KW40Z_connSw_install_dir>\ConnSw\doc\BLEDAUG.pdf
You'll need IAR Embedded Workbench.
And the driver for the KW40Z serial port.
Also, how to program the KW40Z with IAR Embedded Workbench