Rinse lemons and score peels about ¼ in. deep down length of lemons, spacing slashes about 1 inch apart. In a 2- to 3-quart nonreactive pan, combine 2 ½ cups water, kosher salt and lemons. Bring to a boil over high heat, then reduce heat, cover and simmer until lemon peels are tender when pierced, about 12-15 minutes.
With a slotted spoon, transfer lemons to a pint-size widemouthed canning jar with a rubber ring seal (so salt water doesn’t rust the metal). Reserve the salted water.
Add cloves, bay leaf, cinnamon stick, coriander seeds and black peppercorns to the jar. Press lemons down slightly to release juices. Pour enough of the reserved salted water over them to cover completely and seal with the lid.
When cool, chill at least 5 days, turning jar occasionally (lemons may darken a little), or up to 3 months. To use, lift lemons from liquid, scrape out soft pulp, and sliver or chop peels.