Heat 1-2 inches of oil in a small pot. Use a cooking thermometer to make sure the oil is around 350°F (180°C). It should sizzle when you sprinkle some batter droplets into it.
Whisk the sesame sauce ingredients in a small bowl. Dissolve the cornstarch in the water before adding it to the mix. Set this aside to give it some time for the flavors to come together.
Mix the batter ingredients (flour, cornstarch, salt, pepper, and seltzer water) in a medium-sized mixing bowl with a whisk or fork. It should be a similar consistency to thick pancake batter.
Break the frozen vegan chicken strips into bite-sized pieces about an inch long. Heat them in the microwave for 15 seconds if they're too hard to tear, although it's best to keep them as cold as possible until cooking them.
Arrange a frying station so that you can easily dip the chicken pieces into the batter before placing them in the hot oil. Prepare a cooling rack with paper towels beneath it nearby.
Cook them in batches by dipping 5-10 pieces in the batter, shaking the excess off, and then carefully placing them in the oil. Let the chicken cook for about 1 minute on each side. They will be a very light golden color.
Remove the chicken pieces with a skimmer or metal slotted spoon and place them on the cooling rack.
Heat the sauce in a small pan on medium-low for 3-4 mins or until it has thickened. Next, gently toss the chicken into the sauce. Garnish them with sesame seeds and sliced green onions.