I just switched from Ubuntu, where I can hit the Super key and search for any application I want and just hit Enter. In Lubuntu there doesn't seem to be a convenient way to quickly open an app in such manner?
You have 3 options, Synapse, Kupfer or GNOME Do.
Synapse is a graphical launcher enabling you to start applications and also
to quickly find and access relevant documents and files (by making use of the
Zeitgeist engine).
sudo apt-get install synapse
Kupfer is a summoner/launcher in the style of Quicksilver or GNOME Do. It
can search and browse your files, launch desired applications and object
you need in a quicker way.
sudo apt-get install kupfer
Gnome Do Allows you to quickly search for many items present in your
GNOME desktop environment (applications, Firefox bookmarks, files,
artists and albums in Rhythmbox, Pidgin buddies, etc.) and perform
commonly used actions on those items (Run, Open, Email, Chat, Play, etc.).
Although GNOME Do primarily targets the GNOME desktop, it also works
under other desktop environments.
sudo apt-get install gnome-do
You may find synapse more eyecandy, kupfer is the one that needs less dependencies if that worries you. Gnome Do has also a plugin to be used as dock (not enabled by default) but needs hardware acceleration for it.
All three use or adapt to your current gtk theme so they all look fine.
