Prepare the ingredients. Chop the onions and the leeks.
Heat, in a pan, the olive oil, add the chopped onions and leeks. When the vegetables had sear, add and mix the tomato paste. Needs 10 minutes in low heat. (Mix sometimes)
Add the chosen seafood and the rice, mix and add the water. Season with salt, let it cook in moderate heat for 15 minutes
Finally add the coriander at your taste and lemon juice. Wait 5 minutes until the rice is totally open.