Lab/Border mix dominating

[mrwhite73]

Hello,
We have a 19 month old male black lab/border Collie mix. For the most part he is a great dog but he has some weird traits. For one, he has major separation anxiety when we leave. We've video taped him a few times while we are gone and he never really settles down. He paces and whimpers and then proceeds to go through the kitchen and the trash looking for things to get into. He has also taken to jumping on the kitchen table and laying there while we are gone.
The other problem is his tendency to bully other dogs. He starts out just wanting to run with them but pretty soon he is nipping at them, barking at them and sometimes sitting on them. He has even done this to a 4 week old puppy. He never gets in fights, he knows when to back down and be submissive to other dogs, but when he can, he wants to dominate and he will not pay attention to us.
Any advice would be greatly appreciated.
thanks