I found a program named mouseemu which seems to do what I need.
It can define a ctrl+click as right click.
I used different setting like
mouseemu -middle 0 0 -right 29 272
mouseemu -middle 0 0 -right 29 68
The last number is the keycode for left+click. The number 272 is from the man page of moueseemu. 68 is the code for the click I found out using xev.
It does not work so far.
Any ideas how I can find out the code for left click?