Japanese fried chicken bites (Karaage)

Ingredients

• 500 g skinless, boneless chicken thighs , cut into 2-in. pieces
• 2 garlic cloves , minced
• 1 tbsp minced ginger
• 1 tbsp sake , or dry sherry
• 2 1/2 tsp soy sauce
• 1 tsp sesame oil
• 1 tsp granulated sugar
• 1/2 tsp salt
• 1/2 tsp pepper
• oil , for deep frying
• 1/4 cup potato starch , (or cornstarch)
• 1/4 cup rice flour
• flaked sea salt , (optional)
• 1/3 cup Kewpie or plain mayonnaise , (optional)
• 1 lemon , cut into wedges