Peel the lemon with a vegetable peeler being careful to not peel any of the white layer. Place the chicken and lemon peel with 2 Tbsp. olive oil in a plastic storage bag and marinate refrigerated for at least 2 hours.
Bring a small pan of salted water to boil and cook the sweet corn for 1 minute. Remove from the pan and let cool. When the corn is cool enough to handle, cut the corn from the cob.
To make the relish, combine the corn, peppers, tomato, onion, garlic and parsley in a bowl and combine. Add the remaining olive oil and the vinegar; combine and season to taste.
Preheat a grill pan. When the rim is hot to the touch, grill the chicken for 4 - 5 minutes on the first side, turn and grill the other side for 4 - 5 minutes.
To serve, place the chicken on the plate and garnish with the pepper relish.