Preheat grill or grill pan to medium high heat. Clean and oil the grates.
In a bowl combine the turkey, chives, salt, pepper and cayenne. Mix thoroughly and form into 5 even sized patties. Flatten down slightly and set aside until ready.
While the grill is preheating, make the mustard-mayo dressing. Combine everything in a small bowl, whisk together and taste for seasoning.
Grill burger patties 5-6 minutes per side, or until cooked through (165 degrees). Remove and let rest for a couple of minutes.
While the burgers rest, grill the English muffins 1-2 minutes per side or until lightly charred.
To assemble the burgers spread some of the mustard-mayo on the top and bottom inside of the muffins. Place a slice of cheese on the bottom muffin, followed by the grilled burger, a couple slices of avocado and a handful of arugula. Top with the top half of the muffin.
Continue with remaining burgers. Serve immediately.
Recipe Courtesy of Megan Mitchell