Light a grill or preheat a grill pan. Rub the corn and poblano lightly with oil and grill over high heat, just until the corn is lightly browned and the poblano is lightly charred all over but still firm, about 3 minutes.
Peel and core one poblano, then dice finely. Peel and core second poblano, rough chop and place in small blender. Cut the kernels from one corn cob. Place in bowl with diced poblano. Add kernels from second ear of corn to blender with poblano. Add 2 tablespoons of the olive oil and 2 tablespoons of water and puree to a chunky sauce.
In a medium bowl, toss the remaining poblano and corn kernels with the remaining 2 tablespoons of oil and season with salt and pepper.
Prepare your steak the way you like. Cut it in thin slices. Spread the poblano corn sauce onto plate and lay slices of steak over top. Spoon the poblano corn salsa over top of steak.