Put the eggs into a small pot, cover with water, and bring to a boil over high heat. Add salt, reduce heat to low, and simmer, covered, for 1 minute. Remove the pot from the heat and let sit, covered, to gently cook the eggs for 2 minutes. Immediately transfer eggs to a large bowl of ice water and let chill for 10 minutes. Drain. Gently crack and peel the eggs. Pat the eggs dry.
Put the tea, rice, and 1⁄4 cup water into a small bowl and let soak for 3 minutes. Drain the tea mixture in a fine sieve, shaking out any excess water. Line a large flat-bottomed wok and its lid with heavy-duty aluminum foil, pressing the foil against the bottom. Spread the tea mixture in the bottom of the wok, sprinkle the flour, sugar, and five-spice powder over the top, and place a small metal heatproof rack over the mixture. Place the eggs on rack spaced 2" apart.
Open your windows and turn on the exhaust fan. Heat the wok over high heat until the tea mixture begins to smoke, 2 1⁄2–3 minutes. Cover tightly with the lid and continue to smoke until eggs are tinged golden yellow, 5–6 minutes. Remove from the heat and transfer eggs to a clean work surface. (Cool and discard the tea mixture.) Slice the eggs in half lengthwise and place each half atop a whole shiso leaf on a platter. Garnish the yolk of each egg with a dollop of caviar and a little of the julienned shiso leaf. Serve promptly.