The seeds and surrounding pulp in tomatoes contain a high water concentration and a bitter flavor. When added to salsa, the seeds can dilute the flavor, making it less vibrant.
Additionally, they can make the salsa watery and negatively affect its texture. By removing the seeds, you’ll get a thicker and more flavorful result that’s well worth the effort.
You can also quarter your tomatoes as you normally would, lay the wedges on your cutting board skin side down, and then use a knife to separate the seeds and pulp from the flesh.
You can discard the seeds and pulp or save them to use in other dishes. Once the seeds have been removed, chop the tomato as desired and add it to your salsa recipe.