Marsh Samphire Salicornia europaea.
Back breaking, muddy and if you forage with a stroppy teen, possibly expensive on the sand shoe front; otherwise foraging samphire is a walk in a salt marsh. Folklore suggests that samphire is best harvested on mid summer's day but this will be dependent upon where you forage. On the Outer Hebrides, I searched and searched but it was into July before I spied a small plant, which could have been mistaken for a rather juicy looking cactus. It's worth losing a shoe to taste glasswort, which has adapted so well to its surroundings. Glasswort, its common name is associated with its use in glass making Some will say that the best plants are washed by the tides but I'm not sure that I could taste the difference. Age is the key. Forage as early as possible before the stems become woody. It's all a bit of an adventure you need to a tide clock or http://www.tidetimes.org.uk/ to establish low tide, decent footwear, a pair of scissors (roots should not be removed) and a bag. Kneeling is my preferred option but test the sand/ mud first for terra firma. Don't muddle Marsh Samphire (of which there are many varieties) with Rock Samphire. I'm told Marsh Samphire is pronounced 'sam fur'. Collectors of Rock Samphire have Shakespearean reference in King Lear, 'A dreadful trade' - it grows on steep cliffs faces. I have however, spied rock samphire on a pebbly beach on the Isle of Skye, so you may well be able to avoid donning climbing gear as you forage.
My thought on cooking samphire is that less is more. We often eat it raw in sandwiches with egg or salmon pate. If you picnic on salt marshes, the cleaner specimens could be added to sandwiches, which have been prepared earlier. If you are lucky, you might spy purple Sea Asters too. These leaves are equally tasty in sandwiches. Marsh Samphire marries well with poached eggs, fish (with a hollandaise, if you aren't on a diet) and lamb. For further recipe tips see http://www.amazon.co.uk/The-Foragers-Kitchen-Fiona-Bird/dp/1908862610/ref=pd_sxp_f_i
I wash and then rinse samphire several times under running water, before using it. I refrigerate my pickings in unwashed state and wash, as required. Traditionally both marsh and rock samphire were pickled, perhaps this was for preservation. In my opinion fresh is best. Identification is pretty easy but if you are anxious check out a decent fishmonger's counter before you head off to the beach