If you browse through the computer, Flash starts automatically, but in the tablet and mobile it is different. Adobe has stopped developing Flash for Android, which means that sites that use Flash do not work.
One solution is to install the Dolphin Brower browser, which supports Flash. You can install it in parallel with your regular browser, so you choose when you want to use it.
In addition to support for Flash, Dolphin has some other fun features. For example, you can navigate by drawing patterns. Surf to pcforalla.se by drawing a P or go to a dating site using a heart. You can also shake the phone and give Dolphin a voice command.
Dolphin Brower is available for both iPhone, iPad and Android, but it is only in the Android version that you have support for Flash. It also requires some manual settings. Learn more about how to do it here: pcforalla.se/flashiplattan.
Download for Android: Dolphin Browser for Android
Download for iPhone: Dolphin Web Browser (MoboTap Inc)
Download for iPad: Dolphin Browser for iPad (MoboTap Inc)