1. Soak wooden skewers for about 1 hour or longer.
2. Cut the shells of the shrimps along the back and devein. Skewer the shrimp from head to tail. Place them in a shallow dish.
3. Mix the coriander, garlic, lime zest and juice in a small bowl. Stir in the chili pepper, soy sauce and olive oil. Set aside.
4. Peel the mangoes, then cut into thin sticks. Place in another bowl, add the red onion and toss with 1/3 cup of the coriander dressing. Chill until ready to serve.
5. Pour the remaining dressing over the shrimp and turn to coat. Cover and refrigerate for 1 hour.
6. Grill the shrimp over medium heat until opaque at the centre; about 5 minutes.
7. Serve with salad.