In a large bowl, combine the ground chicken with panko, scallions, beaten egg, chopped cilantro, ginger, garlic, coconut aminos, sugar, sesame oil, sriracha and a pinch of salt (¼-1/2 teaspoon). Mix with hands till fully (and evenly) combined and form into 4 patties. Cover and chill for at least 30 minutes. 2. Meanwhile, make the spicy mayo by combining the mayo with the sriracha sauce.
Prepare, clean, and oil grill grates and heat to medium-high. Grill for 4-5 minutes on one side, then flip and grill another 4-5 minutes until fully cooked through (165 degrees F) or pan-sear over medium high heat about 6 minutes on the first side and 4-5 on the flip side.
Toast buns (if you like them that way) and spread with spicy mayo, top with butter lettuce, and add mango.