1. Wash the salad and drain it.
2. Cut the avocado in half, remove the pit, and dice the flesh into small cubes.
3. In a bowl, mix together the vinegar, salt, pepper, and olive oil.
4. Sauté the seasoned scallops in a pan with butter for 2 to 3 minutes.
5. Then, pat them dry with a paper towel.
6. Place a mound of mesclun in each plate, add a few cubes of avocado on top, and drizzle some vinaigrette over it all.
7. Arrange the warm scallops and a slice of foie gras around the salad.
8. Sprinkle with chives.