Heat the oven to 425°F. Line a rimmed baking sheet with parchment paper.
Stir 1/2 cup finely chopped fresh dill fronds and tender stems, 1/4 cup olive oil, 1 finely chopped small shallot, 2 tablespoons freshly squeezed lemon juice, 2 finely chopped garlic cloves, 2 teaspoons dried oregano, 1 teaspoon kosher salt, 1/2 teaspoon black pepper, and 1/2 teaspoon red pepper flakes together in a medium bowl.
Pat 4 (6-ounce) salmon fillets dry with paper towels. Place skin-side down on the baking sheet. Spread the dill mixture evenly over the top and sides of the salmon.
Bake until the salmon is cooked through and flakes easily with a fork, 8 to 12 minutes. An instant-read thermometer into the middle of the thickest fillet should register 120°F to 130°F for medium-rare, or 135°F to 145°F if you prefer it more well-done. Serve with lemon wedges.