Prepare the Base: Place the protein, onion, tomatoes, green chili (if using), and water in a 4-quart slow cooker.
Cook the Protein:
Set the slow cooker to low and cook for 6-8 hours or until the meat is tender.
Alternatively, use the high setting for 4-5 hours.
Add Vegetables and Seasoning:
In the last hour of cooking, add the tamarind mix and daikon. Stir well.
In the final 30 minutes, add string beans and eggplant (if using).
In the last 15 minutes, mix in the spinach or turnip greens.
Season to Taste: Add fish sauce to taste for an authentic touch. Serve hot with rice.