How can I get the water that's in my duck, out of my duck?
If water can get in your duck then there's some way to get it out again. I'm assuming they have some kind of hole in their design that allowed the water in. They're either a squeaker or a squirter. The first step is to hold the duck with that hole pointing down and try to squeeze out as much water through that hole as you can. You may have to actually deform the duck a bit, try to make that hole the lowest point of the duck so the water inside will all drain towards it and out. Remember, Rubber Ducks are very resilient and will not be harmed (or upset!) by some hard squeezing. They know it comes from love.
Hopefully you don't have something else you need to get out of your duck?