I'll see if I can type this out so it makes sense...
Start with the pistol pointed at the target and you facing the target, too.
Now leave the pistol pointed at the target and turn your body (to the right for a right handed shooter) so that your chest is facing the side of the pistol.
Firmly grasp the grip of the pistol and lock your wrist.
Bring your other hand over the top of the slide (at the back of it, don't cover the ejection port).
Grab the slide with your palm (or palm and thumb) on one side and all four fingers on the other (kind've like you were going to hold onto it to do a pullup).
Now push both hands together. When the slide is all the way back let go, don't push the slide forward or let it ride through your hand.
This lets you use the muscles of your back, chest and shoulders rather than forearms.
A 1911 has two springs you’re working against, but with striker fired guns (even the small ones) I haven't found anyone that can't work a slide with this technique.
