Whisk soy sauce, rice vinegar, sugar, toasted sesame seeds and green onion in a small bowl and set aside to serve as dipping sauce later.
Cut a potato into small dices first and throw into a food chopper to make a purée.
Mix potato purée, red onion, bacon, flour, potato starch, salt and pepper in a big bowl to make the batter.
In a non-stick pan, add a touch of oil and heat over medium heat, shake the pan around to let the oil spread evenly.
Use a large ladle spoon, carefully pour the batter onto the pan and then form a round shape with the spatula, continue the process to make several pancakes until the pan is full.
Pan fry for about 5 minutes one side. (wait at least 2-3 minutes until the batter is set before shaking the pan to avoid sticking.)
Flip the pancakes around and continue cooking for 3-4 minutes.
Flip the pancake again, turn to high heat, and pan fry for another minute until heated through.