Combine the first 10 ingredients in a large salad bowl. Cover and refrigerate dressing until needed. (Dressing can be made several hours before needed.)
Preheat the oven to 375 degrees F. Line a baking sheet with parchment. Brush the paper with the 1 Tbsp. olive oil. Cut pita bread into small triangle shapes, each about 1½" tall, and set on the baking sheet. Bake 8 to 10 minutes, turning once, or until lightly toasted.
When ready to serve, toss the spinach into the dressing. Divide the salad among 4 to 6 plates. Top with pita chips and cheese. Garnish with lemon slices and serve.
Note: Pocket-less, Greek-style pita (sometimes called
souvlaki pita) is available in the deli department. If you would like lots of pita chips, cut two pita, not one. The leftover pita in the bag can be frozen for another time.