1. In a 1-cup glass measure, mix broth, vinegar, soy sauce, cornstarch, and chili flakes until smooth.
2. Set a 10- to 12-inch nonstick frying pan over high heat. When hot, add 1 teaspoon oil and the soybeans; stir until beans are hot and their skins are slightly blistered, 2 to 3 minutes. Pour into a bowl.
3. Add remaining 2 teaspoons oil, the ginger, and garlic to pan; stir just until garlic begins to brown, about 15 seconds. Add shrimp and stir until opaque but still moist-looking in center of thickest part (cut to test), 2 to 3 minutes. Return beans to pan. Stir broth mixture and add to pan; stir until sauce boils and thickens. Add salt to taste. Pour into a serving dish.