I don't think you can do it. Others have made the suggestion- for time and for material handicaps.
I don't think either is going to happen any time soon. The only thing you can do at this point is to set up a custom game position which favors one player over the other.
There is a lengthy thread here about it. 2random is hacking or something
I am not suggesting you set up a mate in one situation. I hope you will set up something a little more fair.
Hey. I want to play with a friend who is not that good on chess. I want to play with 1 minute and him with 10 minutes of time. What are the settings for that?