1. In a medium saucepan heat the olive oil over medium heat. Once it is hot add the onion and saute for 3-4 minutes.

2. Stir in the garlic.  Add 1/2 cup of flour and reduce heat to low.  Whisk constantly until the flour is lightly toasted, about 2-3 minutes

3. Slowly stir in the milk and cook, whisking frequently, until the mixture is smooth and begins thickening.  This will take 3-4 minutes.

4. Remove from heat and stir in the tuna, parsley, lemon zest, lemon juice, half the salt, and half the pepper.

5. Pour into a mixing bowl and let cool 10 minutes.  Cover and refrigerate at least 2 hours or up to 2 days.

6. Remove the mixture from the refrigerate and roll into 2 inch balls (about 12).   Flatten and place on a parchment paper lined baking sheet.  Freeze for 30 minutes.

7. Pour vegetable oil into a large skillet or Dutch oven so that it is at least 1 inch deep.  Heat over medium high heat.

8. Meanwhile, beat the eggs in a shallow bowl.  Place the panko in another bowl and the remaining flour seasoned with remaining salt and pepper in a third bowl.

9. Dredge the frozen croquettes in the flour mixture, dip into the egg, and then roll in the panko. 

10. Place in the hot oil and fry for 2 minutes per side or until golden brown.  Remove from the oil and place on a paper towel lined plate to drain.

11. Sprinkle with salt and serve with lemon wedges.