In a small bowl, mix together salt, pepper, cumin, chili powder, garlic powder, paprika, and oregano.
Add 2 tablespoons of lime juice and 1 tablespoon of olive oil to the spice mixture and stir to create a paste.
Trim any excess fat from the chicken breasts. Place the chicken between two pieces of plastic wrap and gently pound to an even thickness of about ½ inch.
Coat the chicken breasts thoroughly in the spice mixture, making sure to cover all sides. Place in a sealed container or resealable plastic bag and refrigerate for at least 30 minutes, or overnight for the best flavor.
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Once hot, add the marinated chicken breasts and cook for 6-7 minutes on each side until the internal temperature reaches 165°F.
Remove the cooked chicken from the skillet and cover with foil. Let it rest for at least 5 minutes before slicing.
In the same skillet, add the sliced onions and bell peppers with a pinch of salt. Cook until they begin to soften and caramelize, about 5-7 minutes. Remove from the skillet and set aside.
Slice the chicken into thin strips against the grain.
Wipe the skillet clean and return to medium-low heat. Place a flour tortilla in the skillet and sprinkle a layer of shredded cheese on half of the tortilla.
Add some of the sliced chicken and sautéed vegetables on top of the cheese, then add another layer of cheese on top of the fillings.
Fold the empty half of the tortilla over the filled half and press down gently. Cook for 2-3 minutes until the bottom is golden brown.
Carefully flip the quesadilla and cook for another 2-3 minutes until the other side is golden brown and the cheese is completely melted.
Remove from the skillet, let it rest for 1 minute, then slice into wedges.
Repeat steps 9-13 with the remaining ingredients to make more quesadillas.
Serve immediately with your favorite toppings.