In a medium bowl, dissolve 2 tablespoons salt in 1-quart cold water. Submerge chicken pieces in brine, cover, and refrigerate for 30 minutes.
MAKE SAUCE:
While chicken is brining, prepare the sauce by combining oil, parsley, lemon zest, lemon juice, honey, oregano, and 1/2 teaspoon pepper in a medium bowl. Transfer 1/4 cup sauce mixture to a large bowl, and set it aside for later.
PREP & COOK CHICKEN:
Remove chicken from brine and pat dry. Toss chicken with remaining sauce mixture.
Preheat a large skillet over medium-high heat. Add the chicken and cook until cooked through and lightly browned, about 5-6 minutes. Add the onions and bell pepper to the skillet and cook until softened, 2-4 minutes.Take the skillet off of the heat and pour in the reserved sauce. Toss to combine and let the mixture sit for 5 minutes.
ASSEMBLE CHICKEN SOUVLAKI PITAS:
Lay a warmed pita on a 12-inch square of foil. Spread pita with about 2 tablespoons Tzatziki.
Place one-quarter of chicken and vegetables in the middle of each pita. Garnish with tomatoes and feta.
Roll pita to look like a cylinder. Repeat with remaining pitas and serve immediately.