In a saucepan over medium-high heat, brown the onion
and garlic in the oil. Season with salt and pepper. Add the tomato sauce or the tomatoes. Bring to a boil, then simmer gently for about 10 minutes. Add the cream and adjust the seasoning. Set aside and keep warm.
In a bowl, combine the vinegar, oil, garlic, red pepper flakes
and shrimp. Season with salt and pepper. Refrigerate for
15 minutes to 1 hour.
Preheat the grill, setting the burners to high. Oil the grate.
Thread one shrimp lengthwise per skewer, inserting the skewer along the back of the shrimp to straighten it. Grill the shrimp for 1 to 2 minutes on each side, or until cooked.
Place the shrimp on a platter and sprinkle with the mint. Serve immediately with the warm rosé sauce.