My son is the same age and has been throwing his food since he could pick it up. He eats better when he is in control, since every thing at this age is a control issue. We have removed the high chair and put a booster at our table and I only put a small amount of food on his plate at a time. I sit with him and eat, I tell what a big boy he is and how nice it is to eat at the table.
If he likes the food and is hungry he does not throw any of it. When he does throw the food, I tell him that we don't throw food and take it away, I will wait a few minutes and offer it again. Most of the time if he throws the food it means that he is not hungry, then there is nothing you can do. I offer him a yogurt about an hour before bed and try it all again the next day.
Just keep telling yourself that no toodler has every stared them self, and that he will eat when he is hungry.
One last thing, you might try just feeding him his three meals aday and no snacks, he might just not be hungry if he is drinking a lot of liquids through the day.
Good Luck and stock up on the paper towels.
R.