Hi Corben and welcome to the Disney Parks Moms Panel.
First of all, let me start by saying that my family absolutely love dining at
Sanaa which in my opinion, offers one of the best views at the Walt Disney World Resort with zebras, giraffes and other animals grazing just outside the windows.
As this restaurant does have a specific
lunch menu, I would think it unlikely that you would be able to order from the
dinner menu during lunch. That said, there's certainly nothing stopping you from asking your server if this would be possible when you are seated on the day of your reservation.
If you definitely want to eat something from the dinner menu, I would recommend making an Advance Dining Reservation for a time which falls within the times that dinner is served.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma