How to Make It
Stir together onion, lime juice, and 1/4 teaspoon salt in a small bowl. Gently squeeze and massage onion to release some of its liquid. Add mango and pomegranate arils to bowl, toss, and set aside.
Thinly slice scallops across grain, and place in a medium bowl. Add orange juice and remaining 1/2 teaspoon salt. Let stand 5 minutes.
Divide sliced scallops among 4 plates; top each serving with 1 to 2 tablespoons pomegranate salsa. Drizzle 1 teaspoon olive oil over each plate. Top evenly with chile slices, tarragon leaves, and lemon zest. Squeeze a lime wedge over each plate, and serve immediately.