In a parchment lined sheet tray, layer bottom with sliced shallots. Place salmon skin side down over shallots. (If your salmon is skinned, place it skinned side down over shallots). Brush on oil and sprinkle salt, pepper and oregano over fish. Place a second piece of parchment paper over salmon, pressing parchment onto salmon surface.
Bake for 8 minutes and remove top parchment. Bake for an additional 6-9 minutes depending on the thickness of the salmon filets. They should be just cooked through.
While salmon is cooking, in a medium bowl, combine chopped tomatoes, chopped olives, lemon zest, lemon juice, parsley, salt and pepper. Stir to combine and hold until salmon is cooked.
To serve, place portions of salmon and on serving plates, top with cooked shallots and divide tomato relish over each portion and garnish with a lemon wedge.