Lunch and Dinner is the same menu. The cut off between breakfast and lunch is kind of iffy. Since Lunch/Dinner is the same menu, it's serve all day after breakfast hours, up until the eastbound red eye. East bound red eyes is any flight departing on the west coast at night and arriving in the east coast in the morning.
Don't worry, Virgin America's Lunch/Dinner menu is basically a Dinner Menu on other airline. Often time it's an appetizer, hot entree (2 to pick from), and dessert.