Cut chicken thighs into bite-sized pieces and place in a bowl.
Mix the 1/2 cup cornstarch, flour, salt and pepper.
Beat the egg in a small bowl with the 1 tablespoon of oil.
Mix in the cornstarch mixture.
Add the cornstarch/egg mixture to the chicken in the bowl.
Heat enough oil to deep fry in a large, deep wok or skillet.
Heat oil to 375º.
Fry the chicken in batches so there is plenty of room around the chicken.
Use 6- 8 pieces at a time. Fry on each side 5-7 minutes or until crisp and beginning to brown.
Drain with a slotted spoon and place on a paper towel-lined plate.
Repeat until all the chicken is cooked.
Mix the soy sauce, rice vinegar, sugar and orange zest in a small bowl.
Remove the oil from the wok and wipe out.
Heat over high heat for about 10 seconds and add the other 1 tablespoon of oil.
Add the minced garlic and ginger and stir fry until very aromatic (about 15 seconds).
Add the broccoli and stir fry for another 15 seconds.
Stir in the sauce in the bowl and add it to the wok.
Bring the sauce to a boil.
Add the mirin/saki and the sesame oil.
MIx the /4 cup water and 1 Tbl. cornstarch and add to the boing sauce, stirring constantly until sauce is thickened and bubbling.
Add the cooked chicken coating well with sauce.
Serve immediately over rice.