Heat the oven to 400 degrees. Brush the bread with Salsa Negra on one side and place salsa-side down on a baking sheet. Slide into the oven and toast until crispy, 10 to 12 minutes.
Cut the pork belly into 10 slices (they should be about ¼ inch thick), then cut each slice in half. Heat a large (12-inch) skillet set over medium-high. Lay in the pork belly and brush the top of the pork with Salsa Negra. When browned and crisp underneath, flip the pork over and brush the other side with the salsa. Place the pork belly on toast and garnish with microgreens or chives. Your delicious bites are ready for your guests.