If you shave the top like a pencil you can pry the top lid off after punching the wholes , then scoop out the meat or use a large cleaver to shave the top off and slice an opening in it, drain it and then chop it in half.
The second method takes some practice but its much faster, just be careful.
My family buys two cases at a time and the market owner showed us the cleaver method after musing about our bread slicer/screwdriver/hammer method.
