Cooking know how, step-by-step:

With a sharp knife or shears, cut a neat circle out of the shell top. Use a towel or gloves to protect your hands.  (Stephen Osman / Los Angeles Times)

Remove the cut-out circle (it should be about 3 inches around) from the shell, using the knife and a spoon.  (Stephen Osman / Los Angeles Times)

Discard the liquid from inside the shell, and using a spoon, remove and discard the black parts.  (Stephen Osman / Los Angeles Times)

Spoon out the clusters of orange roe from inside the shell, keeping them as whole as possible.  (Stephen Osman / Los Angeles Times)

Reserve the clusters of roe and carefully rinse out the inside of the sea urchin shell. Then, place crushed ice inside the sea urchin shell and arrange the clusters of roe on top of the ice.  (Stephen Osman / Los Angeles Times)