Help with Wall renovations

Hi All,
Any help on the following would be appreciated!

1. Cutting a hole in a wall to open up 2 rooms a bit more. I want to cut a section out of the middle of an existing wall. I've checked with an architect and it's not a load-bearing wall and the frame is steel. Any pointers on the best way to do this or things i should check/know before I get stuck into it?

2. Moving a wall/knocking down then rebuilding a wall... The walk-through pantry in the kitchen is built as a separate room - with a small (maybe 1 metre wide) wall extending from the main wall in the kitchen and then a door between this and the opposite wall to close it all in (if that makes sense??).
We want to move this small wall and door back a few feet to close in the pantry and make more space in the kitchen. Would I be better off knocking down the wall and rebuilding a new one further back or is there a way of just moving this wall back to where I want it?

If anyone's got any tips on tools/plans of attack for either of these DIY jobs, it'd be appreciated!
Many thanks,
Woosh