To Buy: 
Farmed prawns are available whole and sold fresh. Buy from the fish market. For both cooked or green prawns, look for a firm body with moist flesh and the shell tight and intact. There should be a pleasant fresh smell and no sign of black.
To Store: 
Whether in the refrigerator or freezer, leave prawns in their shell. This protects them against dehydration, keeping in moisture and flavour.  To refrigerate, place cooked prawns in a covered plastic container or in an airtight plastic bag on a plate.
Tips & Tricks: 
De-vein by slitting the centre back with a very fine-bladed knife and pull the vein out. 
A serve of prawns is equal to about 15 prawns.
Cooking Tips: 
Do not re-cook cooked prawns. Green prawns are can be grilled, barbecued, stir-fried, deep-fried, or boiled. Prawns are translucent when raw and turn white with pinkish bands when cooked. Avoid overcooking.