Rinse rice and soak for 2 to 3 hours. Drain and set aside.
Mix together the chicken, egg, onion, water chestnuts, jalapenos, cilantro, and salt in a bowl. Shape into 24 (1-inch) balls.
Cover a baking sheet with waxed paper. Spread the rice onto a flat surface and roll the balls of chicken to coat with rice. Place the rice balls on the waxed paper, cover with a second piece of waxed paper, and refrigerate or freeze for at least 1 hour. Once chilled, you can transfer the rice balls to an airtight container, separating them with layers of waxed paper, and refrigerate or freeze for future use.
When it's almost time to serve, boil water in a pot or the bottom half of a steamer. Line the steaming basket or top half of the steamer with the lettuce leaves, place the rice balls on top of the lettuce, cover, and steam over a rolling boil for about 30 minutes.
To make the dipping sauce, stir together the soy sauce, lime juice, and simple syrup. Serve in a small bowl alongside the rice balls.
Recipe courtesy of Alexandra and Eliot Angle, Cocktail Parties with a Twist, Stewart, Tabori & Chang, 2002