In the same pan used for the shrimp over medium heat. Add onion, and bell peppers and stir-fry for 1 minute. Add zucchini, and pineapple and continue to stir fry for 1 more minute. Add garlic and ginger; quickly cook for 20-30 seconds. Pour in sweet and sour sauce, and simmer for 1-2 minutes to thicken. Add shrimp back in the pan and stir to coat. Garnish with green onions, and sesame seeds. Enjoy!