This is a pretty traditional preparation of mussels; steamed in white wine, shallot, and garlic. In this case I added tomatoes, which may or may not qualify this as moules marinieres depending on who you ask. This is pretty much a template recipe with infinite potential variation on flavors. If you like anis, substituting pastis or similar (ouzo, arrack, etc) for the white wine is very tasty. Your mussels must be clean, de-bearded, and alive. The best way to get beards off is a to do a twisting pull with a pair of pliers (demonstrated at about 4:45 in this video by Lil's favorite, Alton Brown). Definitely at no point should they be placed in water; this will kill them, and dead shellfish become poisonous very quickly. You can briefly rinse them in a colander however. Perfect cleanliness is neither possible nor essential, and being overly fastidious will likely just kill them. Let them sit out for half an hour or so before prep, so that the live ones close up tight. Sort through fo...