Pat the shrimp completely dry with paper towels. Wet shrimp will steam instead of crisp, so this step matters more than it looks.
In a bowl, toss the shrimp with the egg white and salt, then add the cornstarch and toss again until each piece has a thin, even coat. It should look barely dusted, not clumpy.
Whisk the mayo, Greek yogurt, honey, lemon juice, and sriracha in a large bowl. Taste and adjust. It should be tangy and just slightly sweet.
Heat the oil in a large nonstick or carbon steel pan over medium-high until it shimmers. Add the shrimp in a single layer, working in two batches if your pan is crowded.
Cook 2 to 3 minutes per side until the coating is golden and the shrimp are just opaque through. Do not overcook, shrimp go rubbery fast. Drain briefly on a rack or paper towel.
Add the hot shrimp to the bowl of sauce and fold gently until coated. Do this off the heat so the sauce stays creamy and does not split.
Pile onto shredded lettuce if using, then scatter with scallions and sesame seeds. Serve right away while the coating still has some crunch.