Bring water and salt to a boil in a 4-quart pot. Add Broccoli florets and cook for three minutes. Remove from heat, drain, and put in ice water to stop cooking. Drain well and place in serving dish.
In a small saucepan saute onion and peppers in 1-tablespoon olive oil until onions are transparent. Add balsamic vinegar and tarragon. Bring to a boil and remove from heat. Whisk in remaining olive oil. Pour over Broccoli, toss to combine and refrigerate.
Hint: To roast peppers, wash and dry, place directly on gas burner on high heat. With long tongs, turn pepper as skin begins to char on all sides. Remove from burner and wrap in plastic wrap and let sit for 10 minutes. Remove from plastic wrap and scrape off skin, remove seeds and stem, slice for salad.