Dissolve bouillon in water. Stir in the garlic, cayenne pepper, salt, and black pepper. Toss the meat in the marinade, cover, and marinate in the refrigerator for at least 2 hours.

Preheat a grill for medium- high heat.

Skewer the beef cubes, using 6 to 8 pieces per skewer OR alternate with vegetables (see cook's note below). Pour the oil onto a plate, and roll the skewers in it to coat them on all sides.

Grill the skewers, turning frequently, until the beef has turned light pink, 12 to 15 minutes.

Cook's Note: Alternate beef with cherry tomatoes, mushrooms, onion, red, green or yellow peppers, cut into 1/2-inch pieces and cook as directed above.