Trim the ends from the lemon and slice lengthwise into ¼-inch wedges. Trim away the flesh so that only about 1/8-inch of flesh remains attached to the peel. Slice the peel crosswise into ¼-inch dice.
Build a very hot fire in your oven, and wait until the floor and walls achieve your target temperature. Flour a board and your hands with rice flour, then stretch and pull the dough (never press) into a roughly 13-inch round or oval; don’t try to make it perfect. Transfer the dough circle to a wooden pizza peel liberally sprinkled with cornmeal. Working quickly, drizzle (or spray) the dough with about 1 tablespoon of olive oil, staying away from the edges. Spread/dollop the leek jam somewhat evenly over the top, leaving a 1-inch border. Scatter the lemon dice, olives, and dill over the top, then lay the anchovies across the dough radiating out from the center like the spokes of a wheel, always leaving a 1-inch border. Jiggle the dough on the peel to make sure its still mobile, then slide it smoothly onto the hot oven floor. Bake until the edges are golden. Retrieve with a metal pizza peel (or a rimless baking sheet), transfer to a cutting board, slice, and enjoy.