The event, which has had a number of sponsors in the past few years, is sponsored this year by Frys.com, an electronics entity, which has donated about $12 million to charities in the Las Vegas area.
The tournament will be played on three courses in its four-day run.
Tway's round included eight birdies. He had a run of birdies from holes 4-8, and no bogeys.
The 47-year-old Tway has not won the tour this year, but has not missed any cuts.
Flesch made six birdies and an eagle at the third hole.
Short beat Jim Furyk in a two-hole playoff last year.