Heat 2 tablespoons vegetable oil in large skillet over medium-high heat.
Spread both sides of each chicken cutlet with total of 1 tablespoon mustard. Dip in bread crumbs. Sauté 2 chicken pieces in hot oil about 3 minutes on each side until golden. Set aside and keep warm. Repeat with remaining oil and chicken.
Cut asparagus spears into 1-inch pieces.
In a medium-size saucepan, bring to boiling water called for in couscous package directions, plus an additional 1/4 cup water. Add asparagus; cook for 3 minutes. Add couscous along with remaining ingredients specified in package directions. Cover; remove from heat. Let stand 5 minutes. Stir in lemon juice, salt and black pepper. Spoon onto platter. Top with chicken.