In a mixing bowl, combine the shrimp with 1 tablespoon of cornstarch, 1/2 teaspoon of salt, and black pepper. Toss to coat the shrimp evenly.
In another bowl, whisk together ketchup, rice vinegar, honey, soy sauce, 1 tablespoon of cornstarch, and 1/4 cup of water.
In a large skillet or wok, heat 1 tablespoon of vegetable oil over medium-high heat. Add the coated shrimp in a single layer and cook for 2-3 minutes until pink and opaque. Remove and set aside.
Add the diced red and green bell peppers, onion, and minced garlic to the skillet. Stir-fry for 3-4 minutes until tender-crisp. Then add pineapple and ginger, cooking for an additional minute.
Return the shrimp to the skillet and pour the sauce over everything. Stir to coat and cook for another 2-3 minutes until the sauce thickens.
Remove from heat and serve over rice or noodles, garnished with sesame seeds or green onions if desired.