Remove kernels from cob; discard cobs and set kernels aside.
Zest 1/2 of lime, place in medium-sized bowl.
Cut lime in half, and juice, adding to the bowl with zest.
Heat large frying pan over medium heat, add 1 tablespoon olive oil.
Add onion to frying pan, and saute for 3 minutes.
Push onion to the side, add remaining tablespoon of olive oil.
Add corn kernels to onion, and saute for an additional 2 minutes, stirring constantly.
Transfer corn and onion mixture to the lime bowl.
Add chili powder, yogurt, and 2 tablespoons feta; stir well to combine.
Divide among 4 serving bowls, if serving as a side.
Top with remaining feta.