The alert is for RAM usage, not CPU.  You don't have much RAM associated with the sensor.  Depending on the version of OS you're running it could be bug based on the code version.  Or you could have an issue with the type of traffic.  If you have RAM...

If you are using Linux, you can use a terminal window to ssh from.  If you are using Windows you can us an ssh client i.e. putty.

SSH to the IP of the VM.  Or go into the vSphere client and access the console from there.

You are probably going to need a little more information than simply an image.  Code version your running etc.  Your alert specifies a memory issue.  Does the alert stay in all the time or come and go as traffic volume increases?  Have you tried incr...

What version of code are you running?  Is anything special going on when the firewall 'crashes', i.e. make acl changes etc?  What do you mean by crash, do you me reboots?  Do you have a crashinfo file, you can check this by do a 'show crashinfo'?  Ar...