Add two of the whole tomatoes to a dry sauté pan with the unpeeled garlic.
*The third tomato will be cut into a small dice later.
Increase the heat to medium-high, and toast the garlic and tomato, moving the contents around frequently as they take on some dark spots of color.
When the tomatoes have taken on some color and the garlic cloves are beginning to soften up, remove them from the heat.
Remove the peel from the garlic.
Remove the core, excess liquid, and seeds from the tomatoes.
Blend the toasted garlic cloves with the seedless tomatoes until you arrive at the consistency of a puree, and set the mixture aside for later.
*This tomato and garlic puree will be added to the pico de gallo mixture described below.
For the pico de gallo, dice the final tomato and season with Kosher salt.
Allow the tomato to sit for ten minutes to drain some of its excess liquid.
In a bowl, combine the red onion, minced serrano pepper, lime zest, lime juice, and fresh cilantro.
After the salted and diced tomato has sat for ten minutes, drain off the excess liquid.
Combine the drained tomatoes with the pico de gallo mixture.
Add the tomato and garlic puree mixture from earlier to the pico de gallo, and season to taste with Kosher salt or more lime.
And voila—You have made yourself some delicious homemade salsa!