Combine the lemon juice, garlic, olive oil, thyme, salt, and pepper in a bowl.
Place chicken in a baking dish and pour the lemon juice mixture over it, ensuring it's fully covered. Let marinate for twenty to thirty minutes.
Preheat the oven to four hundred fifty degrees Fahrenheit.
Bake the chicken for thirty minutes, flipping halfway through.
Meanwhile, combine the dressing ingredients in a bowl.
In another bowl, toss arugula with red onion and cucumber.
Once the chicken is done, let it rest for five minutes, then slice.
Arrange sliced chicken over the salad and top with feta and dressing.
