Heat the olive oil in a saucepan. Add the onions, peppers and garlic and cook until soft, stirring. Over medium heat, this should take about 3 minutes. Add the paprika and tomato paste. Cook 1 more minute.
Add the water, cilantro, lemon and salt. Bring to a boil, cover and cook 20 minutes over medium heat. Taste and adjust seasoning.
About 10 minutes into the time the sauce is cooking, assemble the fish balls.
Either pulse the fish ball ingredients in the food processor, or mix with a wooden spoon. Either way, don’t work it so hard that it forms a paste. You want a light, almost crumbly mixture.
With your hands, lightly knead the mixture for half a minute., the heat of your hands will bind the ingredients together. Form balls the size of ping-pong balls and set aside in a cool place.
Check the consistency of the sauce. If you like it soupy, it’ll be ready in 20 minutes cooking time. If you want it thicker, cook it down some more. When you feel the sauce is to your taste, gently place the fish balls into it and cook 10 minutes.
Serve as an appetizer, although it makes a fine, light main dish for 4 also.