1-First, in a small bowl, whisk together the Greek yogurt, light mayonnaise, lemon juice, parsley, and either the rosemary or thyme until well blended. This creates a creamy dressing that ties everything together nicely.

2-Next, in a medium bowl, combine the drained tuna, chickpeas, celery, and red onion. Make sure to mix gently so the ingredients keep their texture without getting mushy. Once mixed, pour the dressing over this tuna salad and toss until everything is evenly coated, then season with salt and pepper to taste for that perfect flavor pop.

3-After that, slice each pita pocket in half and open the center carefully. Layer in the fresh spinach and sliced tomatoes first, followed by the tuna salad mixture. This step ensures each bite is full of crunch and freshness. Finally, serve immediately to enjoy the sandwiches at their best.