For the Shrimp:

• 1 1/2 lbs large shrimp, peeled and deveined
• 2 Tbsp fresh lime juice
• 2 tsp chili powder (1 tsp regular, 1 tsp ancho)
• 1 tsp ground cumin
• 1/2 tsp ground coriander
• 1/4 tsp cayenne pepper, or to taste (optional)
• Salt and freshly ground black pepper
• 3 Tbsp olive oil or vegetable oil, divided

For the Fajitas:

• 1 small yellow or red onion, halved and sliced
• 2 bell peppers, any color
• 2 cloves garlic, minced
• 3 Tbsp chopped fresh cilantro
• 8 medium flour tortillas, warmed
• Sliced avocado and crumbled queso fresco (optional)