2) Measure 45g of diced peppers into a small bowl and add the mayonnaise, sour cream, coriander, lime juice, ginger, garlic and salt. Stir well and then set aside until required.
1) Meanwhile, in large bowl, beat the egg and stir in the panko, soy sauce, sugar, sesame oil, ginger, garlic, lime juice and zest, chilli flakes and salt. Add the tuna and combine gently. Form the mixture into 4 burgers.
2) Heat the vegetable oil on a nonstick griddle over a medium-high heat. Add the burgers and cook for 3 to 4 minutes per side. Toast the rolls during the last few minutes of cooking.
3) Spread some of the sauce on the roll bottom and add the burger. Top with onion, tomato, sprouts, and additional sauce to taste. Add the roll tops and devour.