In a large bowl, combine ground chicken, dip mix and lemon peel until well blended. Form into four patties.
Heat oil in a large, non-stick fry pan set over medium-high heat. When warm, add patties. Fry until brown and crispy around the edges, about 4–5 min per side, or until cooked through.
While burgers are cooking, toast pitas, if you wish. Cut tomatoes into wedges and measure cheese.
When burgers are done, slide onto warm pitas; top with spinach, tomato, cheese and additional toppings, as desired.