Put the duck in a dish and pour the teriyaki sauce over all.
Wash the lentils and put in a pot. Mix in 2 cups water, onion, bay leaf, thyme, garlic, salt, and pepper. Simmer, covered, for about 15 minutes.
Drain the mixture and place back in the pot. Throw away the bay leaf.
Combine the mango pieces, vinegar, oil, 1 tablespoon water, pepper, and mint in a bowl.
Light a grill. Place the duck on the grill and throw away the teriyaki sauce left in the dish. Grill for 2 to 3 minutes then turn over and cook for another 2 to 3 minutes. Once the duck is done, set on a cutting board.
Separate the baby greens onto 3 plates and place a mound of lentils on top.
Cut the duck into thin slices and set on the lentils.
Pour the mango mixture around the duck and garnish with the mint leaves.