In a small bowl, mix salt, sugar, chipotle powder, pepper and garlic. Rub vigorously into the steak. Place the steak in a sealed container and refrigerate overnight. Place steak over medium high hickory smoke fire and sear for 10 minutes on each side. Remove from heat and allow to sit for 10 minutes. Slice into 1/2-inch slices. Place on arugula and add ragout. Top steak with horseradish sour cream.
Tomato and Wild Mushroom Ragout: In a saucepan place 1 teaspoon oil, garlic and shallots. Lightly brown. In a large bowl, toss tomatoes, mushrooms, 1 teaspoon oil and thyme and season with salt and pepper. Place tomatoes, skin side up, on medium hot grill for 8 minutes. Roughly chop tomatoes and add to the mushrooms.
Horseradish Sour Cream: In a medium mixing bowl combine all ingredients. Mix well.