Will I be able to eat solid food after my sinus grafting? How long will it be until I can eat normally after my sinus grafting procedure?

Yes, of course. You will be able to eat a soft diet for the first several days. I do not recommend anything sharp, crunchy, or hard. These foods may tend to irritate and open up the incision-line, causing more pain and possible infection. As long as you're not eating things too incredibly hard and irritating the surgical site, you should be fine. Keep smiling!
Sinus grafting. It depends on the technique. Some are done through the ridge (crestal approach) others from a lateral window. Sounds technical, but if doctor uses the crestal approach, it's best not to disturb that wound (as it's in the most dependent area of sinus and right on top of ridge where you would chew). For the lateral approach, not much to worry about. And if you're wearing a denture, really no issues.
The. The area will be sore for a few days. However, you can eat your normal diet. This procedure is done from the side and does not affect the area to chew with.