You can experience this if you hit a coin with a hammer a few times.

So the flash could cook a chicken by slapping it

One thing to note, actually cooking something requires an application of heat over time. Instantaneous heat transfer will not cook, it will usually just burn.

Some people say you can use a nuke to cook a pizza if you put it in the right spot, but the same problem would apply.

Related, some guy did actually slap a chicken into being cooked. It was predictably disgusting:

https://www.youtube.com/watch?v=LHFhnnTWMgI

There are so many weird assumptions here. There is more than a hand moving when a slap is performed.

A skilled slapper could put more of their body weight behind the slap. I'd assume at least 40 kg or even more as the average slap.

Not chicken, but someone tried hitting steak with drum pedals: https://m.youtube.com/watch?v=QFTCqnYk5Sw

Average rotisserie chicken is 2 lb? Costco's is 3lb. That would require many more slaps.

Fun fact, 165F is often parroted for cooking chicken, but I urge everyone to go lower. 155-160F results in much juicier chicken. 165F corresponds to instantaneously killing all bacteria. 155F is about 60s, and 160F is 15s.

When Martha from accounting last asked me what my plans were for that night, I told her I was going to slap my chicken.

She won't look me in the eye any more.

What if you just want to warm up some sausage?

There was a viral YouTube video of doing exactly this a few years back.

https://youtu.be/LHFhnnTWMgI

If you could have a superpower, what would it be?

Me: I'd like to be able to slap fast. Like really fast.

I once watched a youtube video where someone built a rig to explore this very question

Didn't someone build a machine to do this

Wait a minute 400°F? What dafuck?