Preheat the oven to 400 degrees . In a bowl, whisk together 2 tablespoons olive oil, the chili powder, 1 teaspoon salt and 1/2 teaspoon pepper; rub all over the steak. In a large, ovenproof skillet, heat 1 tablespoon olive oil over medium-high heat. Add the steak to the pan and cook, turning once, until browned, about 5 minutes. Transfer the steak and pan to the oven; roast until it registers 125 degrees on an instant-read thermometer for medium-rare, 12 to 15 minutes. Let rest for 10 minutes before thinly slicing.
Meanwhile, brush the bread slices with the remaining 2 tablespoons olive oil and arrange in a single layer on a baking sheet; toast in the oven for 3 to 5 minutes.
In a medium bowl, combine the pineapple, cucumber, onion, lime peel and lime juice; season with salt and pepper. Serve with the steak and toasts.