Slice cucumbers into ⅛ inch thick slices. To draw out the liquid for extra crunch: layer the cucumber slice with onions, salt and ice in a glass or stainless steel container and weight with a plate large enough to cover the cucumbers and keep them submerged when the ice melts. Cover and refrigerate overnight. Next day, sterilize three 1L canning jars, along with their rings nd lids, and put them on a clean dish towel or wire rack.
Drain the cucumbers and onions, put them in a large non reactive pot, and add the sugar, mustard seeds, turmeric, celery seeds, vinegar, bay leaf, cloves, and jalapeño. Bring to a simmer over high heat, stirring to completely dissolve the sugar. About 5 minutes. Skim off any foam that has formed at the top.
Divide the batch in three parts for the jars. Ladle the hot vinegar liquid over the cucumbers leaving a ¼ inch headspace. White the rims and threads clean, put the lids and rings on the jars, and tighten the rings. Cool the jars to room temperature.
Refrigerate the jars and let the pickle cure for at least 1 week before eating. Unopened, the pickles will keep for up to 2 months in the fridge.