Bring a large pot of water to a boil and salt it generously.
Fill a large bowl with ice water and salt that as well.
Drop the broccoli into the boiling water and cook, uncovered, until crisp-tender, about 2 minutes.
Scoop them out of the water and immediately plunge the broccoli into the ice water; this stops their cooking and sets their color.
Cool, remove them from the ice water, and pat dry.
Repeat with the asparagus, cooking 1 to 2 minutes depending on how thick they are.
Arrange all the vegetables on a large serving platter and serve with the chipotle dip.
2 cloves garlic
1/2 teaspoon kosher salt
1/3 cup mayonnaise
2 tablespoons buttermilk
1 tablespoon chipotle hot sauce
3 tablespoons minced fresh cilantro leaves
1 scallion (white and green parts), very thinly sliced
1/2 teaspoon finely grated orange zest
For the dressing: Smash the garlic cloves, sprinkle with the salt, and, with the flat side of a large knife, mash and smear the mixture to a coarse paste.
Scrape the paste into a small bowl, add the remaining ingredients, and whisk well to make a creamy dressing.