This is called gustatory rhinitis which is a form of non-allergic rhinitis. There are medicines that can be taken that would reduce these symptoms. This is not typically the result of a food allergy.
Sneezing is done because of some allergy. We can have allergy from different things like dust, chicken feathers, potassium etc. As you specified that you always start sneezing right after dinner, it shows that you have allergy from some specific food like milk, some fruit or anything. So have a check on your daily routine that what diet you normally take. You can also have an allergy test.