Preheat oven to 350°.
Combine lamb, salt, cumin, oregano, and flour, if using. Blend thoroughly.
Form into meatballs. I prefer them smaller with this recipe, about two tablespoons each. Place on a rimmed baking sheet or pyrex pan.
Bake until the meatballs reach an internal temperature of 155°, about 20 minutes. Once out of the oven they should rise to a temperature of 160°, which is the recommended safe temperature for ground meat.
While the meatballs are cooking prepare that tzatziki. First, mince the garlic and put it in a medium bowl with the lemon juice. Then peel cucumber, remove the seeds, and finely dice it. Cut the fresh mint into strips, saving a leaf or two for garnish.
Add diced cucumber, mint, Greek yogurt, and sour cream to the lemon juice and garlic. Mix thoroughly, then season to taste with salt.
Serve meatballs with a generous helping of tzatziki on the side.