In a sauce pan, combine the balsamic vinegar, star anise, cinnamon stick, cloves, and brown sugar. Bring to a light boil, then simmer until it thickens and can coat the back of a spoon. Remove from heat and let it cool. It will also thicken more. If your reduction is then too thick, whisk in a little warm water to loosen. Reserve.
For the Salad:
Slice off the rind of the celeriac and brunoise. In a mixing bowl, combine the celeriac and grapes. Add enough olive oil to coat, and season to taste with fresh lemon juice, kosher salt, fresh cracked pepper, and the red chili flakes. Make sure you add enough salt to bring out the flavors in the salad. Reserve.
For the Scallops:
In a saute pan, heat the oil on high until smoking. Lightly season the scallops with kosher salt, then add them to the pan scored side down while pressing down on each scallop. Cook for about 30-45 seconds on high (don't overcrowd the pan), then turn heat down to medium and cook until the scored side is caramelized, about 2-3 minutes. Flip the scallops over, add some butter to the pan, and baste the scallops with a large spoon for about 1 minute or until the scallops reach medium rare doneness. Remove from pan and slice.
Arrange the salad on a plate. Arrange the scallops on the salad and streak or dot the balsamic reduction around the salad. Garnish with the micro arugula and serve.