Combine raspberries, onion, cilantro, jalapeno (if using), lime juice, salt, garlic, cumin and pepper in large bowl.
Mash gently with a whisk or fork to release berry juices, leaving large pieces of raspberry in the salsa.
Add sugar to taste.
Chill 1 hour for the flavors to blend. Adjust salt, pepper and sugar to taste.
Serve with chips or use as a sauce for fish or chicken.