Step 4) Slide salmon fillet off the foil and onto the grill. Position the length of the fillet perpendicular to the grill bars for easier removal, close the lid and grill for 15 to 20 minutes or until cooked through. (If using an indoor grill pan, cut the fillet in half prior to cooking. Cook for about 4 to 5 minutes per side, using a spatula to turn.)