TO MAKE THE MARINADE: In a medium bowl, combine the olive oil, sesame oil, cilantro, garlic, and ginger. Stir well to blend. Add the salmon cubes and toss gently to coat on all sides with the marinade. Cover and set aside at room temperature for up to 45 minutes. (The salmon can be covered and refrigerated for up to 2 hours. Remove from the refrigerator 30 minutes before grilling.) Soak the bamboo skewers in water for at least 30 minutes, then drain.
Prepare a medium-hot fire in a charcoal grill or preheat a gas grill to medium-high.
TO MAKE THE MOJO: Combine the rice vinegar, cumin, and salt in a measuring cup and stir to dissolve the salt. In a blender, combine the mango, orange juice, and chile; blend until puréed. Blend in the rice vinegar mixture. Taste and add more chile, if desired. Add the cilantro and blend, with a quick on and off, just until mixed through. Transfer to a bowl or sauceboat and set aside.
To assemble the skewers, thread a cube of salmon, followed by a piece of red pepper and green onion, on a skewer. Repeat the process 3 more times. Repeat with the remaining 7 skewers. Season each skewer with a little salt, rotating to season evenly.
When ready to grill, brush the grill grate with vegetable oil. Place the skewers directly over the medium-hot fire. Cover the grill and cook on one side, about 4 minutes. Turn and cover again. Cook about 4 minutes longer, or until the salmon is almost opaque throughout, but still very moist.
To serve, have ready 4 warmed dinner plates. If serving the skewers over rice, arrange some rice in the center of each plate and place 2 skewers on top. Drizzle some of the mojo over the top and around the perimeter of each plate. Serve immediately. Pass the extra mojo at the table.