Put the ribs in a large stockpot. Add cold water to cover the salt and bring to a boil over high heat. Reduce the heat to medium-low, skim the foam, cover partially, and simmer for about 1 1/2 hours, or until fork-tender. Drain and set aside until cool enough to handle.
Combine the oil, tomato paste, sherry, onion, garlic, brown sugar, Worcestershire sauce, and honey in a glass or ceramic bowl and whisk until mixed. Rub the mixture into the meat, cover, and set aside for no longer than 45 minutes at room temperature or for as long as 4 hours refrigerated.
Prepare a charcoal or gas grill. Lightly spray the grill rack with vegetable oil cooking spray. The coals should be moderately hot to hot.
Lift the ribs from the marinade. Transfer the marinade to a saucepan and cook over medium-high heat until boiling. Reduce the heat to medium and simmer briskly for 5 minutes. Cover and keep warm.
Put the ribs on the grill, meat side down, cover and grill for about 10 minutes. Turn and grill for 8 to 10 minutes longer, or until nicely browned. Cut between the ribs and serve with the marinade.