Cut the potatoes in 3/8-inch slices. Then stack cut pieces of potatoes and cut them into 3/8-inch square pieces. Submerge the potatoes in a large bowl of water and let sit for 30 minutes. This will help leach the excess starch from the potatoes and keep them from oxidizing.
While potatoes are soaking, prepare the sauce: Combine all ingredients in a nonreactive pan and heat over medium-high. Adjust heat to a simmer and reduce by half.
Heat a heavy stock pot with the oil to 325 degrees F over medium heat. (Use a candy thermometer to check the temperature.) Remove potatoes from the water and pat dry. Carefully add 2 handfuls of potatoes to the hot oil. There should be at least 1-inch of oil above the potatoes. Cook for 5 to 7 minutes or until potatoes are light brown. Remove potatoes, with a slotted spoon, shake off excess oil and place on a rack to cool. Repeat until all of the potatoes are par-cooked.
After all the potatoes have been par-cooked, heat oil up to 350 degrees F over medium heat. Add 2 handfuls of par-cooked potatoes, and cook for 2 minutes or until golden brown. Remove from oil, with a slotted spoon, shake off excess oil. Transfer potatoes to a serving bowl and season lightly with salt and pepper. Repeat this method until all potatoes are fried.
To serve: Drizzle sauce over hot fries and garnish with toasted sesame seeds.