I don't see a constitutional right, do you ?
This from www.usconstitution.net:-
The right to smoke would certainly be covered under the 9th Amendment. But, by extension, so is the right to snort cocaine; but it is illegal, and not just at the state level. So perhaps to start, you need to ask, what gives the U.S. the right to make cocaine illegal? From there, you can extend to include smoking.
The Congress has broad powers to regulate most things under the Interstate Commerce clause. Because most tobacco products are created for sale outside the state they are created in, the Congress can tax and regulate tobacco products. If cigarettes were only consumed in the state they were created in, the Congress may not be able to do too much about the issue. It would likely, however, have the power to ban smoking in all government buildings, seeing how it has the power to set rules for federal agencies, and, by extension, their facilities.
You may have trouble arguing that the Federal Government has a similar right to regulate other public places, because it exerts no direct influence. However, it can make funds for schools, for example, contingent upon it being a non-smoking area. The powers granted agencies such as the FDA would allow it to ban tobacco outright, I suspect, even given its wide usage; the FDA may even be able to ban smoking in public places, though I'd have to check its rules and the U.S. Code governing the various agencies.