Mix water, soy sauce, chili sauce and cornstarch in a measuring cup. Heat oil in a large skillet until hot but not smoking. Add bell pepper, snow peas and scallions. Stir-fry over high heat 3-5 minutes until tender-crisp. Reduce heat to medium-high, add shrimp and stir-fry 2-3 minutes until shrimp start to turn bright pink and opaque. Stir sauce, pour into skillet and bring to a boil, stirring often. Cover and cook over medium-high heat 1-2 minutes, stirring once, until shrimp are opaque at the center. Stir in cilantro and serve immediately.