Drain white beans and combine with capers. Spread bean mixture out in a 13" X 9" baking pan. Thinly slice lemon and remove seeds. Put lemon slices on top of beans.
Combine olive oil, Dijon, salt, thyme, and pepper in a small bowl. Rub all over chicken thighs. Place chicken thighs on top of lemon slices, and nestled in slightly. Add 1/3 cup water to the pan.
Roast chicken for 35 minutes, checking halfway through to make sure it's not burning. Cook until chicken reaches internal temperature of 165 degrees F.
Transfer chicken and beans to a platter and garnish with parsley.
Notes
*If you prefer a vegetarian dish, substitute large 8 portobello mushrooms for chicken thighs and decrease cooking time to 20 minutes.