Heat grill to medium (350° to 450°). In a large bowl, mix 1 tbsp. oil, the garlic, and 1/4 tsp. each salt and pepper. Add kale and toss to coat well. Dump onto grill, quickly arrange in a single layer, and grill, turning once, until streaked brown, 3 to 5 minutes. Set aside to crisp up, then slice into ribbons about 1/2 in. wide and 3 to 4 in. long.
Brown pancetta in a medium saucepan over medium heat, about 4 minutes (if using speck, don't cook). With a slotted spoon, transfer pancetta to paper towels. Add enough oil to fat in pan to make 2 tbsp.
Add rice to pan, reduce heat to medium, and cook, stirring, until rice starts to toast slightly, 1 to 2 minutes. Add onion, 1/2 tsp. salt, and 1/4 tsp. pepper; cook until onion is softened, 2 to 3 minutes. Add enough broth to just cover rice; cook, stirring constantly, until liquid is absorbed. Continue adding broth to just cover rice and stirring until it's barely tender, 15 to 18 minutes. If needed, add more broth so risotto is loose-textured; it will thicken a bit as it stands.
Remove risotto from heat and loosely fold in pancetta, mascarpone, walnuts, butter, and tomatoes. Fold in most of kale and spoon into a serving dish. Top with remaining kale and serve immediately.
*You can buy speck on amazon.com
Note: Nutritional analysis is per serving.