Not responding to them when they are begging will make them realize they are not going to get anything out of it!

Ignore Lil Bit when he/she begs. Don't make eye contact
Give praise when good things are done, and a big strong NO when Lil Bit does something you don't want him/her to do!

As for feeding, they get treats in the morning and when I get home from work they both get 2 cups of ProPlan dry lamb & rice, and they split a can of ProPlan. Once in a while Buddy will keep licking the bowl, so I dump more dry in, and he'll eat it.
When I first got them both they were so underweight I free fed them both for a year, Buddy would eat all day long, and Sierra would pick here and there, but would eat a good amount once a day. They both still could stand to gain more weight, but Buddy, because of being under so much stress (he is deathly afraid of my hubby) has stopped putting weight on. He's at 82 lbs, and Sierra is skinny also, but her build goes along with it, she's tall and thin.