Chop the water spinach into 3 inch pieces. Wash and rinse 4-5 times to remove the grit and sand. Drain well and set aside.
In a wok or deep pan, heat the oil over medium high heat. Add garlic and Thai chili peppers and cook for 30 seconds.
Toss in the water spinach and stir fry until slightly wilted.
Create a small well in the center and add the shrimp sauce along with 2 tbsp of water. Mix the shrimp sauce and water until smooth.
Stir fry the water spinach with the shrimp sauce until completely cooked. Taste to adjust seasoning as needed. If it is too salty, add a few more tablespoons of water. If it is lacking flavor, add more shrimp sauce, a teaspoon at a time.