About one hour before smoking, make the dry rub. Combine all ingredients in small bowl; mix well. Pat ribs dry with paper towels; generously coat both sides of ribs with rub. Set aside at room temperature for 1 hour.
Meanwhile, make the sauce. Combine all ingredients in medium saucepan; bring to a boil over medium-high heat. Reduce heat and simmer 15 minutes until slightly thickened, stirring frequently. Cool to room temperature; cover and refrigerate.
Heat charcoal or gas grill for indirect cooking at 250 to 300 degrees F. Add drained wood chips, if using.
Place the ribs, meaty side up, over a drip pan and cook for 2 hours. Spray both sides of ribs with tamarind juice. Add about 12 coals to a charcoal grill every 45 minutes or so to maintain the heat.
Continue cooking ribs for 1 to 2 hours more until very tender, spraying with tamarind juice every 30 minutes. Add more coals as needed to maintain temperature for a charcoal grill.
Move ribs over direct heat on grill and brush with sauce. Cook for about 5 minutes until sauce is set. Turn ribs and repeat with more sauce.
*Tamarind juice can be found in Asian or Hispanic food section.
Serving Suggestions: Make these smoky-sweet ribs your own by using different flavors of jam for the barbecue sauce-cherry, plum, and currant would all be good. Alongside, serve grilled corn and a tomato-cilantro salad.