LOL...sounds like my son!!! Feeding from his high chair is by far better than trying to eat their food like mine does. Forget the timeout...not going to work and you'll really be punishing yourselves instead. His attention span isn't that long. My son pushes the limits daily and I tell myself, that if I react showing frustration or raise my voice, it's a sign for him to continue doing what he was doing, which is getting a reaction out of me. I have learned w/my 16 1/2 month old that when he wants to throw that temper tantrum, I let him, and I 'encourage it'. I'll kneel next to him and ask him if he needs to throw a temper (as we call) and I'll insist that he does it right away, right there and then if he doesn't I will tell him, okay, I'm going to do...(whatever it was that I was doing) and he looks at me like, oh okay, I'm still not getting what I wanted. Or I like to flick his finger or leg as an attention getter. He'll be opening and closing the dishwasher door and I'll tell him no, no and the 3rd no I also ask, 'do you need a flick or swat'? And he'll say 'NO' and I'll tell him, okay then don't do that and I'll move him to something else that he can play w/. And sometimes, when 'no' doesn't work like standing on his little chair, I tell him you're going to bo boom-boom! And when he does, I say, see mommy told you, boom-boom it hurt huh. And of course I'll cuddle him and reassure him he's fine but remind him that standing on his chair he'll go boom boom.
At this age, I would suggest that you start introducing the 1-2-3 and then take it away or remove him from whatever and give an appropriate item he/she can play w/. Also a flick or a 'thick' pinch on the leg/arm as an attention getter is something to consider.
Whatever you decide to do, make sure you are consistant with it and follow through. My son knows certain signs for words and believe me your child knows what he is doing and he's testing the waters. He's seeing how far he can go without getting hurt or in trouble.
I hope I've given you some idea's on how I am disciplining my little one. Good luck, you'll be fine.