Preheat the oven to 375°. Toast the hazelnuts in a pie plate for 12 minutes, or until the skins are blistered. Transfer the nuts to a kitchen towel; let cool slightly, then rub off the skins. Finely chop the nuts and transfer them to a bowl. Add the parsley, chives, tarragon, chervil, anchovies, capers and shallot. Stir in the vinegar and the 3/4 cup of oil and season with salt and pepper.
Light a grill or preheat a grill pan. Brush the steaks with oil and season generously with salt and pepper. Grill over moderately high heat, turning occasionally, about 12 minutes for medium-rare meat. Let rest for 5 minutes. Slice the meat across the grain and serve with the salsa.