Heat oil in a large non-stick pan and sauté ginger, garlic and onions until soft and lightly browned. Mix in the spices and tomato paste, and fry for a few seconds.
Add in chopped tomatoes, season with salt and cook covered until the tomatoes start to soften and turn to pulp.
Slowly add in the shrimp and tamarind paste, and give it a quick stir to mix well. Cook covered for a few minutes on medium-low heat until the shrimp is cooked through.