These vegetables are used as a bed for Salmon with Warm Passion-Fruit Vinaigrette, but would also be good as a side dish with grilled meat or on their own as a warm salad.
Bring a large pot of water to a boil. Add 1 tablespoon salt and carrots; cook 2 minutes. Add beans, asparagus, and sugar snap peas; cook until tender but still crisp, about 2 minutes. Drain and transfer vegetables to a large bowl of ice water to cool. Drain again.
Heat oil in a large skillet over low heat. Add onions; cook, stirring occasionally, until translucent, 3 to 4 minutes. Add blanched vegetables, tomatoes, remaining 1/2 teaspoon salt, and pepper. Raise heat to medium high; cook, stirring occasionally, until tender, about 5 minutes.
Remove from heat, add basil, and toss to combine.