[Steve_Seattle]

If you look at a map of the Pacific Ocean, there are several underwater mountain ranges that were probably wholly or partially above water at some point. One stretches from Siberia to South America. Maybe these people travelled to South America (and places like Hawaii) by island-hopping when parts of these mountain ranges were above water?

[Theoria]

The 'kelp highway' theory has been around for sometime.

[Pharmboy]

Possible, but not necessary. Asians could have come to the Americas without venturing out over the Pacific. All they needed to do was continue along the shore--coming ashore to camp overnight or for a few days--and then continuing.

By following the shoreline they eventually could have traveled to the coast of Peru, for example.