For preparation I soak my chick peas in cold water for at least 24 hours then I boil them for around 20 minutes in order to make them softer, this process also kills off the seed and prevents the chick peas from sprouting. Its important to soak and boil them as dry chick peas expand a lot when they are put in water and a bait that's not been soaked and boiled properly could be dangerous to the fish so its vital they are prepared correctly.
Chick peas take both flavour and colour very well although I never really bother doing this myself as they work very well in their natural form. I like the fact that they are very visible in the first place and to be honest, I don't see the point in spending money on flavours or colours when it's just not necessary, the carp bait companies might think its a great idea to shift some additives but chick peas really are a superb bait just as they are and theres little point in making things more expensive, carp fishing costs enough as it is!
Presentation wise, I like to fish my chick peas snowman style, rather than fish two of them on a hair I use an Enterprise fake dog biscuit as the top bait. I trim the fake biscuit down with a knife so that it looks just like a chick pea, the cut down fake biscuit is similar in colour to a chick pea and being a pop-up it makes for a superb 'balanced' presentation. The picture below shows my simple knotless knot presentation.
Using a cut down fake dog biscuit also helps keep the bait on the hair, chick peas are quite a soft bait, generally they stay on the hair but sometimes they can be soft enough to come off on a stiff cast, or they may come off when winding in giving the impression you've been fishing without a bait, the fake enterprise dog biscuit prevents this and acts as a buffer for the real pea underneath. I've used this presentation to very good effect when fishing single hookbaits at long range, in fact the picture of the mirror accompanying this piece was caught at 120 yards plus on a single hookbait snowman presentation.
Chick peas are an extremely under rated bait for carp fishing, I've taken them onto some of our most pressured cheshire and shropshire carp lakes and they have never let me down. They make a very good and very cheap alternative to the standard boilie approach that the majority of carp anglers use these days, the only real draw backs with them are that you can't fish them much further than 30 yds without spodding due to their size and weight, and they are not what you would call 'small fish proof'. If your water has a large head of tench and bream and you're targetting carp then chick peas might not be the right choice of bait. If theres no problems with tench and bream on your water then I'd give chick peas a go because the carp love them.