Preheat the oven to 450 degrees. Combine the chicken, onion, garlic and spices in a large bowl. Use damp hands to form approximately 36 1-inch meatballs. Arrange them on an oiled baking sheet.
Bake 15-20 minutes, turning once or twice, until the meatballs are browned and cooked through (they will be firm to the touch).
Make the Tahini Dressing
Combine all ingredients in a mini food processor, or whisk in a medium bowl until smooth.
Assemble the salad
Toss the greens, cucumbers, red pepper, onion and feta cheese in a serving bowl with 2 tablespoons of the dressing.
Serve with the meatballs on top of the salad and drizzle with additional dressing and green sauce. Serve with warm pita or flatbread if you like.
Notes
Refrigerate leftover tahini dressing for up to a week. Stir in a tablespoon or so of cold water to loosen if necessary.
Meatballs may be made 3-5 days ahead of serving. Warm them slightly in a microwave (30-60 seconds) or in a heated pan on the stovetop before serving.