In a small bowl, add olive oil, lemon juice, smoked paprika, garlic and onion powders, salt and pepper. Whisk to combine.
In a shallow flat dish with edges, lay salmon slices and brush with marinade. Marinate from 10 minutes for up to 24 hours. Longer marinating time, more flavorful salmon.
Preheat grill to high heat of 450-500 degrees F. Clean grill well and oil the grates with soaked in oil paper towel. It is important to avoid salmon sticking to the grill.
Place salmon on the grill skin side up, close the lid and grill for about 4-5 minutes.
Check with spatula - if salmon has nice grill marks and comes off the grill easy - you flip it. The key to prevent fillet from falling apart is to move spatula under it slowly and flip.
Cook uncovered for another 3-4 minutes or until thermometer reads 125 degrees F for medium rare or 140 F for medium.