For the chicken: Whisk the olive oil, vinegar, honey, mustard and oregano in a bowl, then pour all but 2 tablespoons of the mixture into a resealable plastic bag. Add the chicken to the bag, seal and turn to coat. Let marinate in the refrigerator for 1 to 2 hours. Preheat a grill or grill pan to medium high. Remove the chicken from the marinade, season with the salt and pepper and grill until cooked through, 8 to 9 minutes per side. Remove and let rest 10 minutes. Spoon the reserved marinade over the chicken and slice. For the dressing: Combine the olives, olive oil, vinegar, sugar, garlic, salt and pepper in a medium bowl. Whisk until combined. Taste and adjust the seasonings (I almost always add a little more sugar). For the salad: Combine the lettuce, tomatoes, cucumber, red onion, olives and half the feta in a bowl. Pour some of the dressing over the salad, season with salt and pepper to taste and toss. Add the chicken. Just before serving, top with more feta, more dressing and pita chips.