The way to do it goes something like this (pseudo-code)
1. When game is loaded grab and store the time, and render the screen.
2. At the start of the next frame grab the time again and work out the time since the last grab of the time. Store the new time.
3. Distance moved = the speed (a constant of your choice for a nice speed) * the time.
For example, you load the game and call System.currentTimeMillis(). You store this in a long variable called lastTime. You render the scene. Get the time again and calculate the difference since the first time, multiplying this time by the speed, say for example the speed is 10 and 0.1secs have passed, you move the paddle 10*0.1 = 1 pixel. You then store the new time into the lastTime variable and repeat?
Hope that is a start, try coding it now