Greek Quesadillas

• 4 large whole-wheat tortillas
• 2 cup cups fresh baby spinach
• 100 g crumbled feta cheese (more or less to taste)
• 50 g sliced Kalamata olives
• 50 g sundried tomato strips
• 296 g shredded cooked chicken
• 1 tsp dried oregano (divided, or to taste)
• 50 g tzatziki (optional)
• 4 lemon wedges (optional)