On a heated oiled barbecue flat plate, cook fish 4 minutes each side or until cooked as desired.
Meanwhile, in a small saucepan, heat oil over high; cook onion and garlic, stirring, until onion softens. Add tomato; cook, stirring, 1 minute. Remove from heat; stir in anchovy, capers, sugar and parsley.
Serve fish with salsa and, if you like, lemon wedges.
