Chopped Greek Chicken Sandwich

Ingredients

• 1 mini cucumber, finely chopped
• 1 large Roma tomato, finely chopped
• 1/2 medium red onion, finely chopped
• 2 garlic cloves, grated
• 2 1/2 cups coarsely chopped rotisserie chicken meat
• 1/2 cup crumbled feta
• 1/3 cup coarsely chopped pitted Kalamata olives
• 1/2 cup tzatziki
• 2 tbsp fresh lemon juice
• 1 tsp dried oregano
• 1/2 tsp black pepper
• 1/2 tsp kosher salt
• Butter lettuce leaves, for serving
• 4 hoagie rolls