As said in comments, the chat usage of *asterisk description* is common in French, too. I have especially seen it on text-based roleplay, it is probably related to didascalies in theatre (couldn’t find a translation), since they have the same role and asterisks are the markdown-equivalent to italics.

As for the oral form, I don’t think that there is a direct equivalent, but for your particular example, you could say

Jo : Alors j’ai demandé à cette fille, « Où est mon asperge »
Michou : Deux claques

the deux claques, said on a particularly blank tone being equivalent to your *slap you*.

In some cases you could also describe your action at the first person

Joe: Aw, come on, let’s burn this cute animal¹
Mickey: *run away*

Jo : Allez, viens, on brûle cette petite chose mignonne
Michou : Bon, je m’enfuis

I have no precise rule for this, though.

_{1. No cute animals were harmed to write this answer.}