What is the best way to remove the newer style picture hooks?
http://www.screwfix.com/sfd/i/cat/72/p1657772_l.jpg

I have some of these on an interior wall which is made of plastered
brickwork. Some hooks have been painted over and some have not.

If I prise the hooks off with a screwdriver (protecting the wall with
a steel rule placed under the screwdriver blade) then I can see I
might take out a chunck of wall plaster.

If I yank the hooks off with a mole wrench then I will probably also
remove plaster. Or maybe the plastic surround of the hook comes away
first and I can then take each pin out with pliers?

Q.1 -- What method of removal miminises the damage to the wall, given
that I already have several of these in the wall?

Q.2 -- Is there a way to fix these in future (perhaps by not
hammering the pins right in???) which permit them to come away with
less wall damage?