Place pre-cooked frozen crab in a strainer over extremely boiling water (fill the strainer with 1/3 water.) Cover securely and steam them more than 10 minutes until its totally heated.
Cook Frozen Crab can be consumed cold without cooking otherwise they just need to be heated without more cooking.

Seafood needs a lesser cooking time than beef, lamb or chicken. Simply because most seafood has a low fat and high water matter and it can easily be overcooked.
However, pre-cooked shellfish can be consumed cold, warm or hot. Over cooking it will harden the meat as it dries out making it harder to get out and over cooking it in submerged water will dampen the meat.

It is therefore advisable for you when cooking a pre-frozen crabs to do the exact procedure in handling and preparing this delicate meat, in order for you to really savor it luscious and delightful taste. Keep in mind that this kind of food is also good for the bosy and diet.