1. Combine the spice rub ingredients in a heavy skillet, mix well, and heat over medium heat, stirring frequently, until spices begin to smoke and become fragrant.
2. Remove from heat, cool, place in a coffee grinder and grind until fine.
3. To make the glaze, combine the pineapple juice, vinegar, ginger, soy sauce, and brown sugar in a small saucepan.
4. Bring to a boil, reduce heat to low and simmer until mixture is reduced by half, about 30 minutes.
5. Add the catsup and cook an additional 5 minutes.
6. Remove from heat, add lime juice, cilantro and white pepper; mix well and set aside.
7. Rub the tuna steaks on all sides with spice mixture.
8. Grill the tuna over a medium fire for 4 to 5 minutes per side, or until center is still slightly pink for medium-rare.
9. Spread pineapple slices lightly with glaze and grill for 2 to 3 minutes per side.
10. Serve grilled steaks on top of jasmine rice with glaze spooned over, top with a slice of pineapple.