Fill medium bowl with ice water; set aside. Bring court bouillon to boil. Add shrimp; reduce heat to low, cover and poach just until shells are pink and shrimp are opaque in center, 3 to 4 minutes. Using slotted spoon, transfer shrimp to bowl with ice water. Drain, peel and devein shrimp. Use a microplane to zest lemons and avoid the white pith. Combine all ingredients for vinaigrette in a nonreactive bowl. Mix gently to distribute ingredients evenly. Let rest for 30 minutes to allow flavors to marry and develop. Combine shrimp and vinaigrette in large nonreactive bowl and mix gently to coat shrimp with vinaigrette. Divide baby arugula evenly and place in the center of 4 wide, shallow bowls. Place ¼ of dressed shrimp on top of baby arugula in each bowl. Spoon remaining vinaigrette over shrimp and arugula. Serves 4 as main course or 8 as a starter.