To make the tzatziki sauce:
Wrap your grated cucumber in a few paper towels or place it in a cheese cloth and wring out as much liquid as possible.
Then add your grated cucumber to a large mixing bowl along with the rest of your ingredients and stir until fully combined. (Taste and adjust your salt and pepper if needed.)
Cover the bowl and keep your tzatziki in the refrigerator while you prepare the meatballs.
To make the meatballs:
Preheat your oven to 400 degrees and line a baking sheet with parchment paper (or spray a baking dish with cooking spray).
Then add your meatball ingredients to a large bowl and mix them together with your hands.
Form the mixture into 1 inch balls and place the balls on your prepared baking sheet. Then place the meatballs in the oven and bake for 15-20 minutes.(Alternatively, you can brown the meatballs in a saute pan before baking them.)
(If browning them first, I'd suggest checking the meatballs at 13 minutes to see if they're done. Sometimes they'll cook faster this way.)
Once done, serve immediately with your tzatziki and lemon wedges on the side.