Squeeze out the roasted garlic and mash. Saute onion in sesame oil until it caramelizes, add roasted garlic and cook 1 more minute to release flavor. Add pineapple,1/4 cup water and brown sugar, cook until sugar is melted.
Combine pineapple juice, soy sauce, lemon juice, rice vinegar, rice wine and cayenne pepper with garlic mixture. Stir occasionally until mixture boils. Reduce heat and simmer for 1/2 hour or until sauce has reduced by half and is thick and syrupy. If sauce is thin, mix 2 Tbsp. Cornstarch mixed with 2 Tbsp. water and stir into sauce over medium-high heat until it reaches the consistency of a thick syrup.
Mix together flour, cornstarch, salt, and sesame seeds in a dish, set aside. Mix in a second dish milk and egg. Dip chicken in milk mixture and roll in flour mixture. Deep fry in hot oil until browned and fully cooked, drain on paper towels.