Fill a medium bowl with cold water and add lemon juice. With a sharp paring knife, cut the top 3/4 inch from the artichokes and trim all but 1/2 inch from the stem. Remove the tough outer leaves. Cut the artichokes lengthwise as thinly as possible, and put into the lemon water.
Over an open fire or a stove burner, heat a cast-iron skillet to smoking hot. (If cooking indoors, be sure to have adequate ventilation.) Working quickly, take slices from the water, shaking off excess, and place in hot pan. After browning both sides, remove to a serving platter. Sprinkle lightly with kosher salt, and drizzle with olive oil and remaining lemon juice.