Combine Marinade ingredients in a ziplock-style bag or bowl.
Marinate shrimp for 30 minutes.
Add 1-2 tbs oil to pan.
As oil heats just slightly, mix soy, vinegar, sesame oil, sugar, and starch in a small bowl and set aside.
Cook chiles for 1 minute.
Add marinated shrimp and cook 1 minute.
Add white onion slices, garlic, ginger, cook 1 minute.
Optional: Add sliced waterchestnuts, cook 1 minute.
Add small bowl of soy, vinegar etc to pan and cook until thick, 2-6 minutes.
Warm the nuts and/or coconut for a minute or so in a separate pan if so desired.
Plate the stir fry and garnish with green onions, peanuts and/or coconut.