Heat the peanut sauce in a medium skillet over medium heat. Mix in the sweet soy sauce and bring to a simmer. Remove from the heat.
Place the pineapple, mango and cucumber in a large bowl. Pour the peanut sauce over top and gently toss to mix thoroughly.
Transfer to 4 serving dishes and top each serving with a squeeze of fresh lime juice and a sprinkle of chopped peanuts.