Rinse and pat dry salmon fillet. Place on a large glass platter or dish.

In a medium-size bowl, combine the sugar, salt, garlic powder, 1 tablespoon of the ginger, 2 teaspoons of the cloves and 2 teaspoons of the cinnamon. Press sugar mixture, about 1/4-inch thick, onto the fleshy side of the fillet. Cover loosely with plastic wrap and refrigerate for 2 hours. Meanwhile, soak wood chips in warm tap water.

Remove fillet from refrigerator. Rinse off rub under cool running water. Dry with paper towels, and let stand at room temp for 20 minutes.

Prepare smoker: Fire up about 7 to 10 pounds charcoal briquettes in bottom of grill. The charcoal is ready when gray and ashy. Reassemble grill, water pan and bottom grate. Pour at least 8 cups hot water into the water pan.

Meanwhile, stir the remaining 1/2 teaspoon each of the ginger, cloves and cinnamon into plum sauce.

Spread the onion slices onto a disposable foil pan or heavy sheet of aluminum foil large enough to hold fillet, but small enough to fit into smoker. Place fillet, skin side down, on top of onions. Spread top of fillet with plum sauce. Place salmon in heated smoker on top rack. Cover grill. Shake excess water off chips; add to charcoal through side door. Cook for 1-1/2 to 2 hours, or until flesh flakes easily with a fork and registers 140 degrees F on an instant-read thermometer. Top fillet with onions from pan, if desired.

To smoke on a gas or charcoal grill: The secret to smoking food is to keep it low and slow. Here are other tips, plus a guide to converting your grill. Cooking time will vary with outside air temperature (the cooler it is, the longer it takes) and how many times you open the cover, so resist that urge! Leave wiggle room in your serving timetable.Thread a probe thermometer through a vent for an accurate cook temp; test finished dish with an instant-read thermometer. Choose lighter, fruitier chips for poultry and fish, pungent or infused ones for pork, beef and game meats. Soak chips in water for about an hour.

Follow the manufacturer's directions for amount of charcoal needed. Do not use charcoal infused with starter fluid because it could make food taste "off." Briquettes are ready when gray and ashy; push to perimeter and place a foil pan with 2 cups of water in center. Place soaked wood chips directly on briquettes; put food on grill rack above pan of water. Add 5 to 7 briquettes to each side every hour if grill temp varies.To convert a gas grill: Heat the grill 15 minutes; turn one burner to medium or medium-high, the other off. Place presoaked wood chips in a foil pan directly on the hot burner; place a foil pan of water on other side. Add food to grill rack above pan of water. For all grills: Use a Charcoal Companion wood chip smoker box for an easy flavor boost; www.companion-group.com.