Go to menu bar, under the GO menu, select Applications. Then look for LimeWire folder inside there. When you find it, open the folder, double-click the program to open it. Once it's open, control-click the LW icon in the Dock & choose to keep in Dock. That's where you will find it in future.

BTW a keyboard shortcut to access your Applications folder is Command-SHIFT-A keys at same time. Command key is the one with an apple icon or the one that shows below.
⌘ SHIFT A