1.5mm allen wrench for front from what I've just read and it should push out with your finger. The rear sight I've not found any quick info so I don't know if there's a allen wrench or or anything. It looks like a dovetail which you'd use a plastic punch with the slide in a very padded vice or a sight pusher if you have one or want to buy one.
I'd suggest a gunsmith though as if they **** it up they'll fix it...