First, line a baking sheet pan with parchment paper (use foil sprayed with cooking spray if you don't have parchment). Start heating the oven to 425°F.
In a small bowl mix together the Dijon, olive oil, lemon juice, garlic, and salt. Whisk very well to combine.
If the salmon filets are not cut, use a sharp knife to cut the salmon pieces into the size you prefer. (I can get 4 nice size pieces that are about 6 oz each from a 1 ½ pound fillet).
Place the salmon fillets skin side down onto the prepared baking sheet. Pat them dry with a paper towel.
Spoon the sauce over the tops of each salmon fillet. coat the sides of the salmon as well.
Top each piece of salmon with a sprinkle off fresh dill and a lemon slice or two.
Bake at 425˚F for 12-15 minutes, depending on the thickness of the filet. Keep an eye on them towards the end of the baking time. Thinner fillets will cook faster and thicker ones may take longer to cook.It should change in color to a lighter pink than it was and flake when pierced with a fork.The internal temperature should reach 140˚F (remove from oven at 135˚F and the carryover heat will continue to raise the temperature as it rests).