Heat the oven to 450° F. Place the salmon fillets on a rimmed baking sheet. Combine the Dijon mustard, olive oil, and thyme. Spread on the salmon and roast until opaque throughout, 8 to 10 minutes.
Brown the bacon in a medium skillet over medium heat, 12 to 14 minutes. Add the peas and ¼ teaspoon each kosher salt and black pepper; cook until heated through, 2 to 3 minutes. Serve with the salmon.