Where a view is linked to a presenter (e.g. your Number/TextPresenters) you can just ask the presenter for its view, e.g.
myNumberPresenter view disable
Note you need to do this in your presenter's onViewOpened method rather than onViewAvailable, since the presenter and view are not yet linked at the point onViewAvailable is invoked.
For views without a corresponding presenter (e.g. StaticText), if you name them in the View Composer (set their 'name' aspect to a String) you can look them up by that name, e.g.
(self view viewNamed: 'myLabel') text: 'This is a label'
Hope this helps.