Make pork: Mix chili powder, garlic salt, onion powder, dry mustard and pepper together and season pork with spice mixture. Let stand at room temperature for 30 minutes. Prepare an outdoor grill for indirect cooking with medium heat, about 350 degrees F.
For a gas grill: Use a smoker box or create one using small, shallow aluminum foil pan. Remove cooking grates. Preheat grill on high. Turn one burner off. Place disposable aluminum foil pan over on burner, adding 1 handful of drained chips. Replace grates. After chips begin smoking, adjust heat to 350 degrees F.
For a charcoal grill: Place large disposable aluminum foil pan on one side of charcoal grate and fill with 1 quart water. Build fire on opposite side, and let burn until coals are coated with white ash. Spread coals in grill opposite pan and let burn 15-20 minutes (you should be able to hold your hand about 1 inch above the grate for about 3 seconds). Add 1 handful of drained chips to coals. Position cooking grate in grill.
Lightly oil grill grate. Grill pork with indirect heat, with the lid closed, for 45 minutes. Add remaining drained chips to box or coals and grill for 45 minutes more. Wrap pork in heavy-duty aluminum foil. Grill over indirect heat, with lid closed, about 1 1/2 hours more. (On a charcoal grill, add more charcoal as needed to maintain temperature, leaving grill lid open for a few minutes to help charcoal ignite.) Unwrap pork and continue grilling until tender and spice coating is crusty, about 30 minutes. Transfer to a carving board and let rest for 20 to 30 minutes. Using a knife and your fingers, pull the pork into shreds, discarding excess fat. Transfer to a bowl and let cool.
Make vegetables: Prepare grill for direct cooking over medium-high heat, about 450 degrees F. Brush grill grates clean. Lightly oil zucchini halves and onion slices (no need to oil corn). Place onion slices, zucchini, and corn on grill and close grill lid. Grill, turning occasionally, until seared. Transfer to a bowl and let cool. Chop zucchini and onion into bite-sized pieces, cut kernels from corn, and return vegetables to bowl. Season with salt and pepper.
Make dressing: Process all ingredients in blender together until smooth and thickened.
Make salad: Mix lettuce, cherry tomatoes, cucumber, radishes, zucchini mixture with corn and onions, and 2/3 cup of dressing in a large bowl. Divide salad among 6 salad bowls and top each with equal amounts of warm pork. Sprinkle with peanuts and serve with remaining dressing passed on the side.