What is nori?
Nori (a.k.a. laver) is a paper like, edible, toasted seaweed used in most kinds of sushi. The nori is actually the part that holds the sushi together.
Nori is usually supplied in packs of 10s or 50s. It arrives in a moist free package, for it must stay dry at all time until used. For that reason it is recommended to get the 10 pack for home use.
How to use nori?
Nori is used in most kinds of sushi. It provides the roll with a unique seaweed flavor, holds many nutritious benefits and most importantly it plays a functional part by keeping the roll together.
A fresh nori should come dry, very dry. Once it interacts with the moist rice, it becomes sticky, hence when wrapping the rice it acts as a firm yet sticky "skin" for the sushi roll. For that reason, in order to make the most of the nori, it must be kept in a super-dry environment before used, or else, it will not stick well and the sushi roll will probably fall apart faster than you can say "Hara-kiri".
Where can I get nori?
In most asian stores and markets probably. There are many producers and suppliers at different costs and values. You should find out which types suits your taste and budget best. It is important to know that nori sheets are hard to store after opening, and usually the remains are thrown away. Therefor it is best to buy the smaller packs of 10 sheets, rather then the larger 50 or 100 sheets packs.