In a bowl, combine your arugulat, blue cheese, pista- chios, lemon juice, olive oil and seasoning. Place to one side.
Using a disk/cookie cutter, shape out 2 circles in the flesh of the watermelon. Pat with a with a paper towel to soak up excess moisture, then lightly brush both sides with oil.
Heat up a griddle pan until smoking hot. Grill over high heat for a few minutes each side, or until black grill marks appear.
Sprinkle a little salt on top, then add your arugula salad and finish with a drizzle of balsamic glaze.