Beat the egg yolk in a mixing bowl, and then mix in the ice water, being careful not to drop the ice in. Mix together the flours, baking powder and salt in another bowl using your hands, and then mix into the egg and water mix. It should be slightly lumpy.
Heat oil to 360 degrees F.
Drain the giardiniera in a colander. Add the rice seasoning into the batter and dip the veggies in. Fry the veggies, a few at a time, until light brown and crispy, 2 to 3 minutes. Drain on paper towels.
Garnish with black sesame seeds.