Remove the shells and veins from the shrimp and clean them thoroughly.
Dice the tomatoes, and finely chop the onion and garlic.
Add olive oil to a pan and sauté the garlic and onion.
When the onion becomes translucent, add the shrimp and stir-fry.
Once the shrimp are cooked, add the tomatoes and season with salt and pepper.
Simmer the sauce until slightly thickened, then sprinkle with parsley to finish.