Shrimp and Lemon Skewers with Feta-Dill Sauce

plain low-fat yogurt

scallion, white and light green parts only, thinly sliced

large garlic cloves, very finely chopped

finely chopped dill

crumbled feta cheese (2 ounces)

Salt and freshly ground pepper

extra-virgin olive oil

peeled and deveined large shrimp

lemons, each cut into 12 wedges