Boil salted water
In a large pot over medium heat, bring 3 quarts of heavily salted water to a rolling boil. Have a large bowl of ice water ready on the side.
Add the broccolini and cook until bright green and tender, about 2 to 3 min Drain and place the broccolini in the ice bath. When the broccolini is cool remove them from the ice bath and place on a paper towel- lined plate.
Toss broccolini in oil
Preheat the broiler to high. In a medium bowl toss the broccolini in olive oil and garlic to coat then arrange in a single even layer on a baking sheet.
Season the broccolini with red pepper flakes and sea salt. Broil until the tips of the broccolini start to char but are not burnt, about 5 to 6 minutes. Remove from the broiler and place back in the bowl.
Finish and serve
Add the red wine vinegar and toss to evenly coat. Serve as a side with grilled or roasted meats and fish.