On top of being delicious and healthy, crab legs are extremely easy to cook. Most crab legs sold in the United States are precooked and then flash frozen to preserve their taste, so preparing them is more a matter of warming than actual cooking. If you've never cooked crab before, follow these simple steps and you'll be eating delicious crab legs in the comfort of your own home in no time.Selecting Crab LegsThe longest crab legs are found on species that come from the Bering Sea, usually snow crabs or king crabs. King crabs are the bigger of the two and their legs have more meat, but their shells have thorny protrusions that can really tear up your hands when you're eating. If you buy king crab legs, be careful! Snow crab legs are a bit smaller but some people think they have sweeter and more flavorful meat than king crab legs.If the crab legs are red that means they've been precooked. Unless you live in Alaska, finding fresh uncooked king or snow crab legs is not usually possible. Quality still varies, so when selecting crab legs make sure they smell fresh like the ocean, not fishy, and try to select legs with easily moveable joints since joints that bend are easier to crack open. You should buy about one pound of legs per person.Cooking Crab LegsSteaming is the best way to cook crab legs, so make sure you have a large pot with a lid and a big metal steaming basket or colander. Crab legs are salty, so rinse your frozen crab legs in water to take off some of the salt before steaming them. Add two cups of water to the pot and put it on the stove on medium-high heat. Put the colander with the crab legs in it in the pot, making sure it's well above the water, and wait for the water to boil.When the water starts boiling, put the lid on the pot and let the legs steam until you begin to smell a delicious crabby scent - generally 5-7 minutes. The crab legs have already been cooked once, so be careful not to over-steam them or they'll get tough and rubbery. Slice some lemon wedges, hand out nutcrackers or pliers for cracking the legs open, and serve the delectable crab legs with melted butter for dipping.