1. In a medium bowl, whisk together the vegetable oil, jam, vinegar and soy sauce. Add the chicken and toss to coat; refrigerated for at least 30 min but can marinate for up to 4 hours.
2. Transfer the marinated chicken to a bowl. Pour the marinade into a small saucepan, boil for 2 min, let cool.
3. Preheat a grill or grill pan to medium. Thread the chicken, plums, and onion onto to 8 skewers. Grill the kebabs, turning occasionally and basting frequently with the marinate during the first 6 min, until chicken is cooked through, 12-15 min.
4. Meanwhile, in a medium saucepan, bring 2 cups water to a boil. Stir in the olive oil and couscous cover and remove from heat and let stand for 5 min. Fluff the couscous with a fork, and the almonds and toss. Serve the couscous alongside the kebabs.