Blanch the tomatoes in salted boiling water for a few seconds, remove the peel. Boil for 15 minutes until tender calamari. Pulp dice tomatoes. Red onion cut into thin rings. Prepare the marinade: Mix the garlic with the lemon juice, mustard, salt and pepper. Whisking, pour in the olive oil. Another hot squid slice and mix with the marinade. Cool, add the tomatoes and onions. Serve portions, sprinkle with parsley and olives.