Add garlic, ginger, soy sauce, 1/8 cup water, brown sugar,
rice vinegar and sesame oil to a medium bowl,
Then add half of the marinade to a ziplock bag
and the other half to a small saucepan and set aside.
Place salmon steak in the ziplock bag and marinate for 30 minutes.
Heat oil in a large skillet. Add salmon steak,
Cook it 3-4 minutes on each side until desired doneness,
Meanwhile heat the reserved marinade in the saucepan
and bring to a simmer.
Slowly whisk in the cornstarch mixture to the marinade and simmer until thickened.