1. Make sauce: Combine all ingredients in a small bowl. Cover and chill.
2. Make pancakes: Preheat oven to 200ºF. In a bowl, beat eggs with 1 1/2 cups water, sesame oil and salt. Whisk in flour until mixture forms a smooth batter. Let stand 20 to 30 minutes.
3. Warm 2 tsp. vegetable oil in a skillet over medium-high heat. Pour in 1/2 cup batter; swirl to form a pancake. Sprinkle with 1/4 cup scallions. Cook until set on bottom, 2 to 3 minutes. Flip; cook other side for about 1 minute. Keep warm in oven.
4. Repeat with remaining batter and scallions, adding more oil to skillet as necessary. Serve with sauce.