Shrimp Fajita Salad

Name: Shrimp Fajita Salad
Ingredients: 3 tablespoons extra-virgin olive oil; 1 large onion, halved and thinly sliced; 3 assorted bell peppers, seeded and thinly sliced; 3/4 teaspoon fajita seasoning; Juice of 2 limes, plus wedges for serving; 1 teaspoon agave nectar or honey; 1/2 cup fresh cilantro, roughly chopped; Kosher salt and freshly ground pepper; 1 1/4 pounds large shrimp, peeled and deveined; 4 flour tortillas; 1/2 head iceberg lettuce, shredded; 1/2 cup pico de gallo