Preheat oven to 400 degrees. Pour melted butter into a large baking sheet with sides, brush to coat the whole surface.
Using a fork, stir together flour, salt, pepper, and red pepper flakes in a bowl. In another bowl, whisk eggs. In a third bowl, place panko bread crumbs.
Coat chicken in flour, dip into eggs, then toss in the panko bread crumbs. Place chicken on buttered baking sheet. Repeat for all remaining chicken strips.
Bake 9-10 minutes, flip chicken over and bake another 9 minutes.
While chicken is cooking, add sauce ingredients (except water and cornstarch) to a saucepan and bring to a boil. Stir together water and cornstarch (making a slurry), whisking it into the sauce until it thickens. Reduce heat to low.
Once chicken is finished cooking, toss or dip chicken in the sauce... turning to coat thoroughly. Serve :)