Yes, you can rebuild a new rim onto the existing hub, either reusing or replacing the spokes (a decision based on age and condition).
However if the ding is so minor that you don't feel pulsed braking and it's only a sound thing, you can probably file or hammer it out. In most cases it involves a bit of both to reduce the amount of metal actually removed. If you have poor metal working skills, and decent bike mehanic can do this for you at a pretty low cost (certainly very low compared to a replacement).
Decades ago I must have offended a witch, and so was cursed with the inability to keep newly built rims dent free for any length of time. Maybe riding tubulars on rainy nights in NYC didn't help. Anyway just about very rim I've ever had on my road bike had some hammer work done but they've never suffered for it.
BTW- de-blipping (new word, call the OED) used to be a very common repair and there was a tool made for this specific job. Just about every decent mechanic had one, and the few that didn't only because they were very good with hammers.
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FB
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Last edited by FBinNY; 08-17-12 at 11:51 AM.