Cut chicken into 1" pieces. Combine 3/4c cornstarch, salt, & pepper in shallow dish. Dip chicken pieces in cornstarch mix to coat, shake off excess, set aside.

Heat oil in a skillet over med-hi heat, brown chicken, set aside.

In the crockpot combine the sugar, soy sauce, pineapple juice, vinegar, garlic, ginger, and cayenne pepper. Stir to mix well.

Add the chicken to the crock pot and cook on low for four hours. Check 20 minutes before serving and make sure your sauce is thick enough. If not, take the remaining 1/4 cup of cornstarch and mix it with 1/4 cup cold water until a slurry forms. Then, gently mix it into the chicken and sauce, being careful not to scrape the cornstarch coating off the chicken. Cook for another 20 minutes, then serve over broccoli and rice.