Wash green onions to remove any dirt. Individually dry them with paper towel to remove excess moisture. Trim off the roots and split the green onions down the middle so the thick white part is split into half. Chop them into 2 inch long pieces and set aside. You should have 2 cups of firmly packed green onions.
Pat dry the squid rings and peeled shrimp with paper towels to remove excess moisture. Set aside.
In a large bowl, whisk together all purpose flour, potato starch, baking powder, garlic powder, onion powder, chicken bouillon powder and salt. Then add chopped green onions, shrimp, squid rings and cold water. Mix together just until combined but do not over mix.
Heat a large non-stick pan (about 12 inches wide) over medium-high heat and pour in 2.5 tablespoon of vegetable oil or any neutral oil. Once the oil is hot, swirl the oil around in the pan and pour in the batter. Evenly spread the batter across the pan with chopsticks or spatula. Scrape out remaining batter with a spatula and pour it over the pancake filling in any holes. Use a spatula to spread the batter evenly so it fills in the gaps.
Reduce to medium heat and fry until the bottom is crispy golden brown and the onions are slightly charred with small holes forming all over the pancake, about 5-7 minutes. Swirl the pancake every now and then so the oil coats the pancake evenly for a golden brown color.
Flip pancake over. Pour remaining oil around the edges of the pancake. Swirl the pancake in the oil to prevent it from sticking. Fry until the other side is golden brown and the onions are a bit charred, another 4-5 minutes. Press the pancake down a few times with the spatula to make the pancake crispy.
Slide the large pancake onto a cutting board and slice with a sharp knife into small squares or wedges and transfer to a large serving plate.
In a small bowl, combine dipping sauce ingredients and serve with pancake.