Remove salmon from the fridge to allow it to come to room temperature while you prepare the vegetables.
Heat the grill or oven to 400°F.
Cut four foil sheets, 12 inches by 18 inches. If desired, line with slightly smaller pieces of parchment paper.
Combine marinade ingredients and set aside.
Chop vegetables into uniformly-sized pieces so they will be cooked at the same time.
Toss with the marinade.
Pat salmon fillets dry. Brush or spray the foil or parchment paper with olive oil, and rub the fillets on both sides with oil. Sprinkle with a little salt and pepper. Place skin side down, one on each of the four packages. Tuck a sprig of fresh dill underneath each and top with a slice or two of lemon.
Arrange the vegetables beside the salmon fillets in each package and drizzle with any extra marinade left in the bowl. Divide the chopped green onions evenly among the 4 packages.
Fold the sides of the foil together, creating a small tent to allow air to circulate, then fold the ends over to seal. Slide the packets on to a baking sheet to transfer to the grill or oven.
Place the foil packets on the grill, close the lid and cook for 12- 18 minutes depending on the thickness of the fillets and the temperature of your grill. If baking in the oven, you may wish to leave them on a baking sheet. Check for doneness by poking the thickest part with a knife. If it flakes easily, or has reached an internal temperature of 140°F to 145°F measured with an oven thermometer, it's done. Some people like to remove it from the heat while it is still a little translucent in the center. It will continue to cook a little in its own heat while you allow it to rest for a few minutes.Broccoli florets should be fork tender.
You can prepare these foil pack salmon meals a day in advance. Refrigerate until you're ready to cook them.