The alternative is to fool the eye... If you know that a dust speck exists in a certain location, try to compose your shot so that the shadows or mid-tones are in that area, thus limiting the eye's ability to see the dust spot.
In the open environment, it is not possible to achieve 100% dust-free sensor, even with the best cleaning tools. Only in dust-free environment, such as a clean room would it be possible, but very expensive.
I have not tried the new Oly P&S which are water-resistant, dust resistant and shock resistant. Those may be dust-free longer than other cameras.