Lemon Vinaigrette: Whisk oil with lemon juice, shallot, honey and salt.
Toss arugula, quinoa and grapefruit segments with Lemon Vinaigrette. Sprinkle with blackberries and pumpkin seeds.
To segment grapefruit, slice off top and bottom of fruit. Using a sharp knife, remove peel, making sure to remove the white pith and outer membrane. Holding peeled grapefruit over a bowl, cut between membranes to release segments.