In a mini food processor, or using a mortar and pestle, mash garlic with the herbs, vinegar, oil, and Dijon mustard until it becomes a paste. Set aside.
Season salmon with a pinch of salt and fresh pepper. Heat a grill or grill pan over high heat until hot. Spray the pan lightly with oil and reduce the heat to medium-low.
Place the salmon on the hot grill pan and cook without moving for 5 minutes.
Turn and cook the other side for an additional 3-4 minutes, spooning on half of the garlic herb mustard sauce.