Here is what you will need:

1/4 cup freshly squeezed lemon juice
1 small shallot or 1/2 small red onion, chopped
1/4 cup pure olive oil
1/4 teaspoon coarsely ground fresh black pepper
4 boneless, skinless, chicken breasts
1/2 pound arugula
a cup or more of grape tomatoes, quartered 
1/2 small red onion, peeled, halved and thinly sliced
2 tablespoons red wine vinegar
2 tablespoons extra-virgin olive oil, plus additional for garnish
Lemon halves, for garnish


Slilce open the chicken breasts, like a book. Starting at the thickest part, you can also pound the breasts to thin them out.

Whisk together lemon juice, shallot, olive oil and black pepper in a large baking dish or large bowl.
Add the chicken, turn to coat and marinate in the refrigerator for 30 minutes.

Preheat grill to high. Remove chicken from marinade, season with salt on both sides and grill for 2 to 3 minutes per side or until golden brown and just cooked through.

While the chicken is grilling, slice up the tomatoes:

Slice or dice the onions:

Combine arugula, tomatoes and onions in a large bowl, toss with the vinegar and oil and season with salt and pepper, to taste.
Place each chicken breast on a large plate and top with some of the arugula-tomato salad. Garnish with lemon halves.