In a medium bowl, combine pineapple juice, sugar, soy sauce, cornstarch, tomato paste, rice vinegar. Stir to incorporate.
Heat wok over medium high heat and add 1 tablespoon oil. Season shrimps with salt and pepper. Cook shrimps for few minutes until done and transfer to a plate and set aside.
Add the remaining oil and saute the onions until soft about 3 minutes then add the ginger and garlic. Add the vegetables and the pineapple. Cook for for few minutes. Return the shrimps and pour the sauce mixture. Let simmer for 2 minutes. Done! Serve with rice.
Recipe by The Gluten Free at https://www.theglutenfree.com/gluten-free-sweet-and-sour-shrimps/