Farro Foundation: In a medium saucepan, combine farro with 3 cups water or broth. If using water, add ½ tsp kosher salt. Bring to a boil, reduce to low, cover, and simmer 20–25 minutes until tender-chewy. Drain excess liquid; cool slightly.
Vinaigrette: In a small jar or bowl, combine olive oil, lemon juice, garlic, Dijon, ½ tsp kosher salt, and black pepper. Shake or whisk until emulsified.
Grand Assembly: In a large bowl, combine cooked/cooled farro, arugula, tomatoes, cucumber, chickpeas, and red onion. Toss with about two-thirds of the vinaigrette.
Searing the Scallops: If present, remove the small side muscle from each scallop. Pat very dry. Season all sides with ¾ tsp kosher salt and black pepper. Heat 1 tbsp olive oil in a large non-stick or cast-iron skillet over medium-high until shimmering. Add scallops in a single layer; sear 90 seconds–2 minutes without moving until a deep golden crust forms. Flip and cook 60–90 seconds more, until just opaque with springy bounce or 52–54°C (125–130°F) internal temp. Remove immediately.
Finish: Divide salad among 4 plates. Top with warm scallops, drizzle remaining vinaigrette, and garnish with dill and parsley.