Place poblano chile on a foil-lined baking sheet; broil 10 minutes or until blackened, turning occasionally. Place blackened chile in a zip-top plastic bag, and seal. Let stand 15 minutes. Peel and cut chile in half lengthwise. Discard seeds and membrane. Finely chop.
Combine the chile, radishes, coconut, lime juice, olive oil, fresh cilantro, and garlic clove in a medium bowl. Cover and marinate in refrigerator for 30 minutes or overnight. Stir in the cubed mango.
Place salmon, skin side down, on grill rack. Grill 10 minutes or until fish flakes easily when tested with a fork. Serve with salsa; garnish with cilantro sprigs, if desired.