I did try recreating the sea urchin spaghetti, and it's actually really easy, especially if you get your sea urchins ready to eat instead of tackling spiky golf balls yourself.   One sample recipe:

http://www.e-rcps.com/pasta/rcp/p_stuv/urchin.shtml

Go easy on the oil, the garlic and the chili...  or don't, but use sake-pickled sea urchin instead, which is cheaper and (IMHO) perhaps even tastier.