Scrub potatoes thoroughly with a brush; pat dry. Cut the potatoes in half lengthwise; cut each half into four wedges.
Cook potatoes, covered, in a small amount of boiling water for 15 minutes or until just tender. Drain and let cool.
Meanwhile, place seeded chipotle chilies in a blender container or food processor bowl. Cover and blend or process until peppers are ground. Set aside. Stir together garlic, olive oil, paprika, cumin, chili powder, black peppers, salt, and ground chipotle pepper in a small bowl. Stir in enough water to make a mixture that's easy to brush on potatoes. Brush chipotle mixture onto potatoes.
Grill potatoes on the rack of an uncovered grill over medium coals 4 to 6 minutes or until edges begin to brown, turning occasionally.
Or, preheat gas grill. Adjust heat for direct cooking. Place potatoes on greased grill rack over medium heat. Grill uncovered as directed in step 4. Makes 6 servings.