Is it possible to have 1 input text field that accepts characters from the user, and as the user types, queries to a webservice are launched, and to update the contents of another component dynamicaly with the results of the webservice (which would be a table below the input text)?
If you prefer to use Wicket form controls and Data Table component then you need to make the call to the REST service in your impl of IDataProvider.
Otherwise, as I explained to you earlier today in your other SO post you can do this directly in JS without Wicket. It is a matter of taste and skills.