DD2 is 16 months and still does this - she thinks it's fun and it is a developmental phase. To dela with it I just remain calm and ask her to keep her food on her plate to reinforce that that is what she should be doing. If she is finished she will say "out" to get down from the table so I let her down if she has had enough.

It does stop and they do grow out of it. You will just have a messy floor for a while until that happens.