Dissect crabs, rinse thoroughly and chop them into chunks. Steam crabs till done.
Chop pineapple, tomatoes, onion and pepper into pieces. Cut chili into rings.
Heat 2 tbsp oil to saute onion till tender, add chopped garlic and tomato chunks.
Add seasonings to ingredients and cook till sauce are chunky, then put in crabs and braise for a while.
Add remaining ingredients to pan and stir well. Dish up and serve.