Add the diced tomatoes, diced tomatoes with green chiles, lime juice, cumin, salt, sugar, black pepper, chipotle peppers, cilantro and onions to a food processor and blend until totally combined. Give it a taste to check for seasoning.
Make the salsa several hours before serving, as it will give the flavors a chance to dance! Keeps in the fridge, covered, for about a week.
1 chipotle pepper will add a little bit of smokey flavor and a little spice, while 3 will add a stronger smokey flavor and a whole lotta spice.