Preheat the oven to 400°F. Line a large baking sheet with parchment paper for easy cleanup.
In a large bowl, combine the halved baby potatoes, 2 tablespoons of olive oil, garlic powder, onion powder, paprika, salt, and pepper. Toss until the potatoes are well coated. Spread them out in a single layer on the prepared baking sheet.
Roast the potatoes in the preheated oven for 15 minutes.
While the potatoes are roasting, prepare the salmon and veggies. In a separate bowl, toss the broccoli and cherry tomatoes with the remaining tablespoon of olive oil, salt, and pepper.
After 15 minutes, remove the baking sheet from the oven. Push the potatoes to one side and place the salmon fillets on the other side of the sheet. Arrange the broccoli and cherry tomatoes around the salmon and potatoes. Top the salmon with lemon slices.
Return the baking sheet to the oven and roast for an additional 12-15 minutes, or until the salmon is cooked through and flakes easily with a fork, and the vegetables are tender.
Serve immediately, garnished with extra lemon wedges if desired.