Preheat the oven to 180C (fan).
Add the chicken into a mixing bowl along with the zest and juice of the lemons, garlic, Dijon mustard, oregano, olive oil, and a pinch of salt and pepper. Mix well.
Spread the chicken out onto a baking dish, then bake it for 40 minutes.
To make the simple Greek salad, add all the ingredients into a mixing bowl and toss together.
Once the chicken is cooked, dish it up, spoon over some sauce, and enjoy.