1. Combine the first 3 ingredients in a bowl, stirring with a whisk.
2. Place peanut oil, curry powder, and chicken in a bowl; toss to coat. Thread chicken onto 8 (6-inch) skewers.
3. Heat a grill pan over medium-high heat. Coat pan with cooking spray. Add chicken to pan; cook 4 minutes on each side or until chicken is done.
4. While chicken cooks, combine 1 1/2 cups pineapple, 1/3 cup red onion, 2 tablespoons cilantro, 2 tablespoons lime juice, and 1/8 teaspoon ground red pepper. Serve chicken with soy sauce mixture and pineapple mixture.