Preheat the oven to 350 degrees
Pat dry the fish fillets, season with salt and pepper, and
arrange in a shallow baking dish.
In a blender or food processor combine the onion, garlic,
gingerroot, tamarind paste, sesame oil, cumin, salt to taste,
and 2 tablespoons water and blend until smooth. Pour mixture
over fish, coating both sides.
Bake fish, covered with foil, in the oven for 20 to 25 minutes,
or until it flakes easily with a fork.
Transfer fillets to a serving dish, correct seasoning, adding
more salt if necessary, and drizzle with lemon juice. Garnish