In a medium bowl, combine together grapes, red onion, basil, balsamic vinegar and olive oil. Season with salt and pepper, to taste. Set aside.
Rub salmon fillets on both sides with olive oil and season with salt and pepper.
Place salmon in hot grill pan, and cook for 4 minutes, or until golden underneath.
Gently turn salmon over and cook the fillets for another 2 to 3 minutes, or until just cooked through.
Remove salmon from the heat and let rest for 30 seconds. Serve with the grape salsa and your favorite steamed vegetable.