COOK rice as directed on package. Meanwhile, combine mangos, cucumbers, onions and 1 Tbsp. of the dressing; set aside.
HEAT remaining 1 Tbsp. dressing and the oil in large nonstick skillet on medium-high heat. Add fish; cook 3 min. on each side or until fish is browned on both sides and flakes easily with fork.
SERVE with the rice and mango salsa.