Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper.
In a large bowl, mix together the oregano, thyme and cumin with 1/2 teaspoon of the salt. Add the chickpeas and then the olive oil, and toss until the chickpeas are evenly coated with the spice mixture. Spread the chickpeas out onto the baking sheet and bake for 20 minutes.
Add the parsley leaves to the bowl where the chickpeas were tossed. Gently stir the parsley leaves so they are coated with the leftover oil and spices and set aside.
While the chickpeas are cooking, whisk together the yogurt, lemon juice, tahini, garlic and remaining 1/2 teaspoon salt in a medium bowl. Refrigerate until ready to serve.
Remove the baking sheet from the oven, sprinkle the parsley leaves on top of the chickpeas and cook for another 10 minutes. (Try to avoid the parsley touching the parchment paper, as it is more likely to burn this way.)
To serve: On a large platter, put down a layer of the chopped lettuce and top with the tomatoes and cucumbers. Scatter the crispy chickpeas over the top of the salad. Drizzle the yogurt and tahini dressing over top of the chickpeas, sprinkle with the sesame seeds and serve with hot sauce on the side if desired.
Be careful when removing the chickpeas from the oven, as they have a tendency to pop. Allow to the chickpeas to cool slightly before moving them around on the baking sheet in order to prevent this from happening.