Toast the cumin, fennel, and Sichuan peppercorns in a dry skilletYou can also use a popcorn popper for this. over medium heat until fragrant, 1 to 2 minutes. Remove from the pan and let cool. Once cool, grind the spices, the garlic powder, and the salt in a coffee/spice grinder.
Cut the lamb into 1/2-inch cubes, but don't trim away any of the fat. Sprinkle the cubed meat with half of the spice mixture and thread onto skewers, leaving just enough room at the end to safely handle. Line the skewers up on plastic wrap, roll into a cylinder, and refrigerate for at least 1 hour before cooking.
Prepare a grill by lighting 4 quarts of charcoal (1 starter chimney's worth) or turning a gas grill to medium-high. Make sure the grates of the grill are clean and debris free. Quickly wipe the hot grill grate with a towel dipped into a little canola oil, then grill the skewers to medium-rare, about 2 minutes per side. Sprinkle the skewers with more of the spice blend between turns.
It is absolutely imperative that you consume your chuan'r with several cold beers. After all, you're not going anywhere at this hour, right?