2) Stir the parsley mixture with the lemon zest, juice and olive oil in a small bowl. Set aside.
For the chicken:
1) Preheat a griddle pan or nonstick skillet to medium high. Spray the chicken breasts lightly with the olive oil and season with salt and black pepper, to taste.
2) Cook the chicken, in batches if necessary to avoid crowding the pan, turning once, until cooked through, about 2 mins per side. Put each chicken breast on a plate and top with the gremolata.
For the rocket salad:
1) Toss the rocket, radicchio and tomatoes with 1 tsp of olive oil and the lemon juice, salt and pepper.
2) Divide the salad between the plates. Serve immediately.