In a large zipper bag, whisk together the olive oil, vinegar, and lime juice. Season with chili powder, paprika, onion powder, garlic, cayenne pepper (if using), salt, and black pepper. Add the turkey and stir to coat. Seal, and marinate in the refrigerator at 1 - 24 hours.
Whisk to together dressing ingredients and set aside.
Preheat grill to medium-high. Brush corn and asparagus with 1 Tbsp of oil. Place turkey and corn on the greased grill. Close lid and grill, turning as needed until turkey as reached and internal temperature of 74ยบ and corn is charred and tender; about 15-20 minutes. Remove to plate and keep warm.
Add asparagus to grill; grill, covered, turning often until tender-crisp, about 5-7 minutes.
Slice turkey breasts diagonally. Cut corn from cobs. Cut asparagus into 1-inch pieces. In a large bowl toss together corn, asparagus, lettuce, tomatoes and green onions. Transfer to plates. Top with turkey slices. Drizzle with dressing.