Hey Lilprecious.
Offhand, most salsas have tomato, onion, capsicum..
Let me go look in one of my books for something more specific...
500g fresh tomatoes, diced
1 tablespoon oil
1 onion, diced
1/4 cup vinegar
1 tablespoon sugar
1 teaspoon cloves, ground
1 teaspoon mustard (powder) or dijon mustard
2 tablespoons tomato paste
pinch cayenne pepper

Saute onions with cayenne, mustard and cloves.
Add tomatoes, vinegar and sugar, cook for 20 minutes. Let cool.
Add tomato paste for colour just before serving.

For you, I would maybe only use half a teaspoon of mustard powder, and perhaps omit the cayenne pepper.
That's what the recipe says (from The Body Shop cookbook), but I would probably substitute the vinegar for lemon juice (or at least some of it), and also add in some rough chopped flat leaf parsley and basil, and some parmesan (omitting the cloves).
But I would also add in chilli, cos I really like hot food. And maybe some chopped green capsicum for extra colour.
For bruschetta when I make that, from memory all I put in it is chopped tomatoes, small amount of that purple chopped onion, and green capsicum, along with chilli, parmesan and basil. Spoon over thick sliced crusty toasted bread spread with basil pesto.
Mmm, now I am hungry.
Let me know how you go!