Combine the lime juice, paprika and garlic in a jug. Place the chicken in a shallow glass or ceramic dish. Add half the lime juice mixture to the chicken and turn to coat. Cover with plastic wrap and place in the fridge for 20 minutes to marinate.
Meanwhile, cook the barley in a large saucepan of boiling water for 20 minutes or until tender. Rinse under cold running water. Drain. Transfer to a large bowl.
Heat a non-stick frying pan over high heat. Spray with olive oil spray. Add the corn and cook, stirring occasionally, for 2 minutes. Add the capsicum and green onion and cook, stirring, for 1 minute or until the corn is light golden. Add the corn mixture, parsley and remaining lime juice mixture to the barley. Taste and season with pepper. Stir until well combined.
Wipe the pan clean with paper towel. Place over medium-high heat. Spray with olive oil spray. Drain the chicken from the marinade. Cook for 4 minutes each side or until cooked through. Set aside to cool slightly.
Thinly slice the chicken. Divide the barley mixture among serving bowls. Top with the chicken to serve.