PLACE pumpkin, evaporated milk, peanut butter, chopped green onions, garlic, cilantro, lime juice, soy sauce, sugar and cayenne pepper in blender or food processor; cover. Blend until smooth. Combine 1/2 cup pumpkin mixture and chicken in medium bowl; cover. Reserve remaining pumpkin mixture. Marinate chicken in refrigerator, stirring occasionally, for 1 hour.
ALTERNATELY thread chicken, bell peppers and green onion pieces onto skewers. Discard any remaining marinade.
PREHEAT grill or broiler.
GRILL or broil, turning once, for 10 minutes or until chicken is no longer pink. Heat remaining pumpkin mixture; serve with satay.
NOTE: If using wooden skewers, soak in water for 30 minutes before threading.