I have used those puck lights quite a bit. I still do.
They have a metal frame with 3 holes in the top and the puck sort of cradles inside of it, right?
If you have any sort of canopy, you can screw the cradle into it, or, you can use the double sided spongy tape from gorilla or loctite and cut enough fine strips (usually takes about 5 pieces) and it will stay there solid.
Just put a heavy book on it for a coupple hours or so to make sure that it gets a good seal if you go the tape route.