Spray grill rack with nonstick spray. Prepare barbecue ( medium-high heat ). Whisk mustard, mayonnaise, tarragon, and brown sugar in medium bowl. Brush mustard sauce generously on both sides of pork cutlets.
Grill pork until just cooked through and firm to touch, 2 to 3 minutes per side. Transfer to plates. Serve with Grilled Red and Green Cabbage Slaw.