There is a variety of evidence pointing to pre-Columbus contact of Europeans and people of the Mediterranean, and even some of Chinese contact.
These are scattered bits and pieces. Nothing that enables us to say anything more definitive that they were pre-Columbus contacts.
The obvious pre-Columbus contact was of the Vikings. While variously argued by scholars, the discovery of Viking villages upon the receding of the glaciers in Newfoundland and Greenland confirms not merely occasional contact as when a ship becomes lost at sea, but actual colonization. As to what became of these Viking settlements, it appears that the Little Ice Age had something to do with it.
As for Islamic contact with the Americas, and Muslim presence at the founding of the country, there is very little tangible evidence, but there is some. Columbus was in contact with the Islamic world and, perhaps, was tipped off not only to the trade winds but also to the existence of a land mass in the vicinity of the Americas. His map of the world was terribly off, being much smaller than what had been known since the days of ancient Egypt ad Greece about the circumference of the world. But, this map could have reflected an attempt to reconcile the position of “China” relative to Europe, given knowledge that there was a great land mass not far west in the Great Sea.
Regarding slaves, taken from west Africa, it is likely that most of them were captured by Muslim tribes and then sold to Europeans. But, possibly among the slaves were some Muslims. While stripped of their clothing and possessions, it is possible those Muslim slaves remembered enough of the teachings of Islam to appreciate the similar teachings of Christianity. But, African animists clearly embraced the Gospel message, so the forced or fraudulent conversion of slaves to Christianity was hardly necessary. Remember, it was among the mixed-race slaves of the Roman Empire with whom early Christianity spread.
That three names could be found among the rosters of the Continental Army that might have been a Muslim is hardly indicative of anything. All three names were apparently taken by the men after they had gained their freedom. Possibly one or more of the three were Muslims, but there were no Korans or Mosques or any other indication of community worship. By the time of Washington’s march to Yorktown, the Continental features many men of color. My state of Virginia gave freedom to many who joined in the struggle and we had a very large population of free men of color as a consequence. So, if there were any, they were only a few.
Paradoxically, the Civil War is proof of no American Muslims at the time of the Revolution. We clearly had Muslims in our army during the Civil War. But, they came here from Morocco and elsewhere in the Islamic World, not from among our native born population. Some came here as runaway slaves, and joined in our effort to free the slaves; and, some came here as free men in order to free the slaves in this country.
Hillary Clinton has her purpose in saying what she did, grasping at mere traces of history to make a political statement.
Sorry, my point was that there were many men of color in our army and in the sate militias, but only three names that could be said to be Muslim. These names are the exception that proves the rules (there were very few if any Muslim among the black patriots in our amy during the Revolution).