I know this is possible but please don't use applet unless you have too! The planets need to align to ensure the user is in the correct browser with applet support enabled and java installed on thier PC. We abandoned this in favor of NCL long ago and never looked back.
I deploy the Client Launcher in an installer file to all our PCs in our company. This way the client launcher install is controlled (and the installer shows up in Windows Programs). With the client launcher in a predictable path on the PC, I don't see why its not possible to link directly to at least open the launcher. Check this thread for more info Java version client sadness - #5 by ryanjmclaughlin
file:///C:/ProgramData/Ignition%20Client%20Launcher/clientlauncher.exe
The key is to make the client launcher work best for your situation and everyone is very different.
Also, I believe there was an idea request out there, but it would be cool if the future client launchers had a URL handler so Ignition projects could be directly launched. Ex: ignition:// url format.