Between pieces of plastic wrap or waxed paper, place each chicken smooth side down; gently pound with flat side of mallet or rolling pin until about 1/4 inch thick. (I usually cut each piece of chicken in half crosswise to make it even thinner)
In a small bowl, beat egg and 2 Tbsp lemon juice with fork or wire whisk. In a 1-gallon resealable food storage plastic bag, mix Bisquick mix, paprika and sesame seeds.
Dip chicken into egg mixture, then place in bag. Shake until chicken breasts are well coated. In a 12 inch skillet, heat oil over medium high heat. Add chicken; cook 6-8 minutes turning once, until chicken is no longer pink in center.
Meanwhile, in a 1-quart saucepan, heat all sauce ingredients except onions over medium heat, stirring occasionally, until thickened and bubbly. Spoon sauce over chicken before serving; sprinkle with onions. Serve on a bed of couscous or rice.