I agree with Kate and Deborah...rememeber that toddlers' appetites vary a LOT. Tyler will go for days living on nothing, then will suddenly eat me out of house and home. His appetite decreases throughout the day too. If he skips dinner, I'll offer a healthy snack before bed. And we did away with mid-morning and mid-afternoon snacks around 18 mo. He just didn't want to eat that much food, and even now, he only gets a snack if it's a hungry day. I just go with the flow as best I can and remember that healthy kids don't starve themselves! Choices between 2 things help too. Even if your LO can't verbalize, he can still point to what he wants. And if he wants nothing, you can try again later.
We also have a house rule that all eating happens sitting at the kitchen table. How you offer the food is really up to you...the thought of Tyler wandering around with food in his mouth or hands or having a graze, leaving, then coming back over and over drives me bonkers, so we've never gone down that road.