There is more than one thousand words in SOWPODS dictionary suitable as first move for OSKI: 3-letters long with various letters. If you want play variant with random letters you can use one dice, roll it four times and use next pdf doc for determine your random word.
For example for values 5, 6, 5, 3 is your word WAY. If for your combination, there is not word, you must throw dice again.