In a bowl, combine chicken breasts, olive oil and vinegar and season with cayenne pepper, black pepper and sea salt. Mix well to evening coat and season chicken, cover and refrigerate for 20 minutes while you prepare the remaining items.
In a bowl, whisk together the olive oil, vinegar, garlic, herbes de Provence, parsley, Maille Dijonnaise, cayenne pepper, black pepper and sea salt. Divide mixture into two equal parts. One part will be for basting the chicken breasts as they grill and the other will be the dressing for the green bean and bacon salad.
To prepare the salad, blanch the green beans in boiling salted water for 1–2 minutes until they are bright green and just tender. Drain and rinse under ice cold water to chill, drain again.
In a bowl, combine blanched green beans, bacon, red and green onion and chopped parsley. Add the first batch of reserved dressing, season to taste with a pinch of cayenne, black pepper and sea salt. Mix well, cover and refrigerate until needed.
Preheat grill to medium high (350–450ûF).
Grill chicken breasts for 6–8 minutes per side, basting with reserved dressing liberally during the last half of grilling, until chicken is fully cooked but still moist and juicy (to an internal temperature of 170ûF).
Place the green bean and bacon salad onto an oval platter. Top with grilled chicken breasts. Drizzle with any remaining dressing and serve immediately.