One of the Face Advantages, Unstoppable, allows Wei to 'Ground 'n Pound'. How exactly do I 'Ground 'n Pound'?
To perform a Ground 'n Pound, you have to ground your enemy, then, well, pound them.
First, you need to activate the Face Meter by filling it up with successful attacks on enemies. Once the Face Meter has been activated, the Ground 'N Pound is as simple as tackling an enemy (running towards them with Space + F on the PC) and then pressing the attack button to punch.
Wei will hold the enemy down and you'll be prompted to repeatedly press the attack button, allowing you to punch them into submission:
I've found that pulling this off can be a bit tricky since it's not always convenient to tackle an opponent (instead of just grappling them) in the short period that the Face Meter is active.
You can perform a similar move during normal combat, but you're restricted to a much less devastating single punch after the tackle.