Prepare rice according to package directions; keep warm.
Place a large skillet over medium-high heat until hot; add 2 Tbsp. sesame seeds, and cook, stirring constantly, 3 to 4 minutes or until seeds are toasted. Remove seeds from skillet.
Cut chicken into 1-inch pieces. Combine chicken and cornstarch, tossing to coat.
Heat 1 Tbsp. olive oil in skillet over medium-high heat. Cook chicken pieces about 5 minutes on each side or until done. Reduce heat to medium, and stir in 1/2 cup pineapple juice and next 3 ingredients. Bring to a boil, and cook, stirring occasionally, 1 minute or until thickened. Remove skillet from heat.
Remove chicken mixture to serving platter. Sprinkle with toasted sesame seeds and chopped green onions. Serve with warm rice.