Can I write a letter to an inmate who is in Alternative Work Program ? And how ?

Call the place, or the person, and find out how exactly to address the letter. For some programs if you don't address it exactly right, then they won't deliver it. They'll open and read the letter before giving it to him.

Most of the programs allow you to write. The fact that your from asia shouldn't matter, accept that it takes longer and costs more. But once it hits the US mail, then it shouldn't matter where it came from.

To save long distance phone call, email a friend and have them call. Or if you have the programs web page, you could email them to get the exact address.

You can but corrupt screws are free to withhold your mail and nothing can be done about it.