You need to have a Dart-VM (Dart-Runtime) installed in order to be able to execute Dart applications on the command line/server.
As far as I know there is no way to create a standalone executable, at least no easy one.
It is technically possible to create an executable that contains the Dart-VM but there are no tools available yet that generate that for you. I don't think the path using Dart2JS will help much. Dart2JS aims primarily at browsers but I have heard that some try to use Dart2JS to run Dart code with Node.js but I don't know if that really works.
This similar question contains some links that may be of interest to you: Embedding Dart into application