Stir together mayonnaise and Sriracha.
Add shrimp, stirring to evenly coat.
Heat a large skillet (not nonstick) over medium-high until hot, about 3 minutes.
Add shrimp in a single layer and cook, flipping once, until golden brown and just cooked through, 3 to 4 minutes total.
Sprinkle with cilantro and sesame seeds.
Serve immediately.
