It is also possible to say "she is wearing skimpy clothes".

Revealing clothes definitely sounds more natural than exposing clothes, but either are perfectly acceptable. If you had asked me without giving examples, I would have told you to say she is wearing revealing clothes, so I think that would be the phrase you should use.

So scantily clad should be equal to scantily dressed, right?

The word is "scantily." Yes, to revealing, no, to exposing. You could also describe her as being scantily clad (as opposed to scantily dressed) . The meaning remains the same. J.