Coat skillet with cooking spray, heat over medium high heat. Saute celery and onion til tender. Place in a bowl with cream cheese and lemon juice and red pepper. Add breadcrumbs and dried dill, tuna and egg white. Divide into 8 equal portions. In a skillet over medium high heat, cook 4 cakes, 2 minutes on each side. Repeat at remaining 4 cakes. Combine sauce in small bowl. Serve with tuna cakes.