This is the way that kids develop and learn about cause/effect and physical/tactile sensations with food etc. The only reason parents don't like this area of their learning is because it results in more cleanup and work for us! It is really best to let them play and learn while they are still young and little. Don't worry, you won't have an 18 yr old that throws her food!
You can always try the suggestions of giving less food, removing the food when she seems disinterested or done, participating in the feeding and fun so she isn't seeking negative attention, completely ignoring the throwing EVERY time and NEVER giving even negative attention for it, teach the sign for 'all done' and implement it for lots of things (not just meals).
If you change your way of thinking and treat this stage of growing/learning the same as we treat the fact that babies use diapers....it's messy and takes some work, but it's all just a stage that will pass, you (and she) will eliminate so much frustration regarding meal time and enjoy each other and the dinner table more :-)
Best wishes!