1/3 cup gf teriyaki sauce 3 Tablespoons frozen pineapple juice concentrate 1-1/2 Tablespoons rice vinegar 1/2 teaspoon cornstarch 1/2 teaspoon gf hot sauce, plus more to taste 1/2 fresh pineapple or one 20 ounce can unsweetened pineapple chunks, drained 2 teaspoons vegetable oil 1 Tablespoon fresh ginger, minced 1 pound large shrimp, peeled and de-veined 1 bunch scallions, trimmed and cut into 1" pieces Salt to taste
In a small bowl, whisk together teriyaki sauce, pineapple-juice concentrate, vinegar, hot sauce and cornstarch. Set aside.
If using fresh pineapple, peel and cut into 1/2" pieces.
In a wok or large skillet, heat 1 teaspoon oil over high heat until hot. Add ginger and stir-fry until fragrant, about 30 seconds. Add shrimp and stir-fry until pink, 2 to 3 minutes. Transfer to a bowl.
Heat remaining 1 teaspoon oil until hot. Add pineapple and scallions and cook, stirring occasionally, until pineapple is slightly browned, about 4 minutes. Add reserved sauce mixture and shrimp and heat through, about 1 minute. Season with salt to taste.