Preheat grill to high heat. Clean and oil grates well (this will help prevent the fish from sticking). Pat fish dry with a paper towel. Brush with olive oil and sprinkle with salt, cumin, garlic and black pepper on both sides. Set aside.
In a large bowl, combine tomatoes, jalapeno, red onion, cilantro, garlic, lime juice, extra virgin olive oil, salt, cumin and pepper. Stir well. Add more salt to taste, if needed. Set aside.
Place black sea bass on the grill, skin side down. Grill until fish is opaque and flakes easily with a fork. Flip halfway through cooking time. These filets tend to be thin, so they will cook quickly. Remove from grill. Spoon salsa over fish. Sprinkle with sea salt.
Serve with lime wedges and additional salsa. You can also sprinkle with feta cheese, for a salty, briny twist.