I have this small wall that has surface imperfections (not holes).
Heard about something called "skim coating" where you mix water with
drywall compound and apply it to the wall.

1) How thin should I make the compound before applying it ? Is it
just water + compound?
2) Can I use a heavy-duty textured roller brush (loops) to apply this
compound ? I have this one from Lowe's already:
http://www.lowes.com/lowes/lkn?actio...00000159-LR638
(sorry if the link doesn't come out). I am ok with a "textured"
effect - at least it will be consistent.

I've also seen something called "texture paint" which you apply over
the drywall to also mask surface imperfections - is this a better or
worse alternative to skim coating with joint compound?

Thanks.