Such a feature has been discussed before on the big meta (How Do I Opt Out of Privileges?). It has been rejected, with a very simple reason: Nobody (i.e., not even the casual voters) should vote for duplicating unless they are 100% sure it is the correct action.
If you are not sure, you should simply comment, not vote to close, and see where it goes.
The notorious dupehammer gives superpowers to learned members of the community, but here are the rules:
You can instantly close as a duplicate any question that was originally asked with a tag you have a gold badge for.
You can instantly reopen any question closed as a duplicate that was originally asked with a tag you have a gold badge for.
No. In the same way that mod votes are binding as we are expected to have experience in using them, once you have shown knowledge in a particular tag it's expected that you do know about it. So you are in a position to judge if a question should be closed.