Chicken Shawarma with Shredded Lettuce Salad

Name: Chicken Shawarma with Shredded Lettuce Salad
Ingredients: 1/3 cup extra-virgin olive oil; 6 tablespoons fresh lemon juice; 5 garlic cloves, minced; 1 teaspoon kosher salt; 1 tablespoon sweet paprika; 2 teaspoons ground cumin; 1 teaspoon ground coriander; 1 teaspoon ground cinnamon; 1/2 teaspoon crushed red pepper; 1/2 teaspoon ground turmeric; 1/2 teaspoon black pepper; 2 pounds skin-on, bone-in chicken thighs; 2 medium red onions, cut into 8 wedges; 1 cup crème fraîche; 1 tablespoon finely grated lemon zest; 2 tablespoons plus 1 teaspoon fresh lemon juice; Kosher salt; Pepper; 2 tablespoons extra-virgin olive oil; 1/2 pound head of romaine lettuce, thinly shredded (4 cups); 1/2 cup cilantro leaves; 3 scallions, thinly sliced; 2 tablespoons finely chopped jalapeño (from 1/2 chile); Pita bread and green olives, for serving