Holding the body backside up, place your right thumb in the joint between the upper and lower shell on the side opposite the mouth. Your palm will be stretched across the top of the shell. Hold the bottom of the crab in your opposite hand. Force your thumb in and pull up and back to your right until shell snaps off. Pour any juices in the shell into a small bowl. Cut the body into quarters with a large knife. Twist the legs off the body. Crack lightly in several places with a nutcracker and set aside.
Heat the olive oil in a very large ovenproof saute pan over medium-high heat until hot. (You may need 2 pans.) Add the crab and garlic, and toss well. Saute for about 10 minutes. Season, to taste, with salt and pepper and mix in lemon juice. Saute for another 5 minutes, then add parsley. After another 1 or 2 minutes, remove the crab and serve in the newspaper lined cans.