Well since they came from a Japanese supermarket...
Japanese style is also nice.
Use a tempura batter rather than a breading before deep frying. Serve with ponzu as a dipping sauce or better still, granish with mitsume (thick "eel sauce").
Ponzu Recipe
Ingredients:
1/2 cup good soy sauce
1/3 cup uzu (Japanese citrus juice)
1/4 cup dashi
2 tbs (white) rice vinegar
Technique:
Combine. Serve.
Mitsume Recipe
Ingredients:
1/2 cup good soy sauce
1/2 cup dashi
1/2 cup mirin
1/2 cup sugar
Technique:
Combine all in a small pan. Set over a low flame and slowly reduce to a nappe consistency, roughly a 60% reduction. Remove from fire and allow to cool. Note that sauce will continue to thicken as it cools.
Oishi desu,
BDL