Fajitas de Pollo (Chicken Marinated with Onions and Peppers)

Ingredients

• 4 Tbsp vegetable oil, divided
• 2 Tbsp lemon juice
• 3 cloves garlic, finely chopped
• 1⁄2 tsp oregano
• 1⁄2 tsp crushed red pepper flakes
• Salt
• 3 boneless, skinless chicken breasts, cut into chunks
• 2 onions, thinly sliced
• 1 red bell pepper, thinly sliced
• 1 yellow bell pepper, thinly sliced
• 1 green bell pepper, thinly sliced
• 4 tortillas
• Fresh cilantro, finely chopped