Step 1

Cook bacon in a dry medium skillet over medium heat, turning slices occasionally, until brown and crisp, 5–8 minutes. Transfer to paper towels; let cool.

Step 2

Cook ginger in a small saucepan of boiling water 1 minute. Drain ginger and rinse under cold water; set aside.

Step 3

Whisk soy sauce, tahini, miso, fish sauce, sesame oil, sugar, and 2 Tbsp. lemon juice in a small bowl until smooth.

Step 4

Whisk egg yolk and remaining 2 Tbsp. lemon juice in a medium bowl to combine. Very gradually stream in ½ cup vegetable oil (almost drop by drop), whisking constantly until mayonnaise is emulsified and thick. Still whisking constantly, gradually add soy sauce mixture, then remaining ¼ cup oil. Thin dressing with a tablespoon or two of water if needed; you want it to be the consistency of heavy cream. Season with salt and pepper.

Step 5

Toss chicken and ½ cup dressing in a large bowl to coat. Add lettuce and another ½ cup dressing and toss again; season with salt and pepper. Crumble bacon over.

Step 6

Transfer salad to a serving bowl or platter and drizzle another tablespoon or so of dressing over salad (you may have some left over). Top with scallions, sesame seeds, and reserved ginger.

Step 7

Do Ahead: Dressing can be made 1 day ahead. Cover and chill.