Rub the stingray pieces with the juice of the lemon and salt. Keep aside.
Dilute tamarind paste in warm water. Keep aside.
Grind shallots, garlic, ginger, lemongrass, fish sauce and chili paste to form a paste.
Heat oil in a pan.
Add the paste and cook for about 3-5 minutes until it turns a darker shade of brown and becomes clumpy and thick.
Pour in tamarind juice and sugar and let it simmer on medium low until it has thickened.
Adjust seasoning if necessary.
Allow to cool.
Meanwhile, preheat oven to 200xbaC.
Tear out a large piece of aluminium foil, large enough to fold twice over to form a pocket for the sting ray to sit in comfortably. Tear out a slightly smaller sheet of baking paper and place on aluminium foil.
Place 1-2 tablespoons of tamarind chili paste on the baking paper.
Place the sting ray on top.
Pour the remaining paste on the top.
Wrap the stingray well with foil, making sure sides are pressed in and sealed well.
Place on the baking sheet and bake for 15-20 minutes or further, depending on the size of the fish pieces.
Remove from oven and open foil carefully. If the flesh is all white and flakes easily, itu2019s done.
Garnish with red onion slices, lime wedges and sprigs of coriander.
Serve hot with Salad and Rice/ Mashed potatoes.