Preheat the oven to 375°F.
In a large bowl stir together the yogurt, coriander, cumin, turmeric, garlic powder, cayenne, garam masala, paprika, lemon juice, ginger, salt, and beer.
Add the meatballs, toss to coat.
Line a baking sheet with aluminum foil, spray with cooking spray or grease well with olive oil.
Add the meatballs.
Bake until cooked through, about 10-15 minutes (cooking time will depend on the size of your meatballs, as well as how cold they are).
Add the cucumber to the center of a few paper towels or a clean kitchen towel. Squeeze to remove excess liquid. Add the cucumber to a bowl along with the yogurt, cilantro, green onion, coriander, cumin, salt, and garlic.
Add the meatballs and riata to the rolls, serve immediately.