If you own a food processor, you can mince the garlic, ginger, shallot, serrano, and cilantro together by pulsing it until finely chopped.
In a large mixing bowl, stir together the garlic, shallots, ginger, serrano pepper, cilantro, fish sauce, lime juice, mustard and salt. Add the chicken and mix with your hands until the vegetable mixture is incorporated, but the chicken is still coarsely combined. Form into 6 even patties, 2-inches thick, and set aside on a plate.
Heat a thin layer of oil in a large nonstick skillet. Cook the burgers over medium-high heat until nicely browned and cooked through, about 4 minutes per side. Remove to a plate to rest for 5 minutes.
Serve the turkey burgers in lettuce leaves or on toasted buns and top with a dollop of sriracha mayo. Garnish with fresh cilantro and serve the remaining mayo on the side.