Open Reynolds(R) Slow Cooker Liner and place it inside a 5- to 6 1/2-quart slow cooker bowl. Fit liner snugly against the bottom and sides of bowl; pull top of liner over rim of bowl. Place chicken in Reynolds(R) Slow Cooker Liner. Place onions and bell peppers on top of chicken. Mix salsa, fajita seasoning mix and cayenne pepper in a medium bowl.