Open-Faced Burst Tomato & Pesto Sandwiches

Combine all of the pesto ingredients (except the olive oil) in a food processor. Pulse a couple of times until combined, scraping down the sides as needed. Slowly add the olive oil until your desired consistency is reached - I used 1/4 cup because I wanted a chunkier pesto. Taste and adjust seasonings as needed.
Heat 1 tbsp of olive oil in a pan over medium heat. Add the tomatoes and a sprinkle of salt, pepper & red pepper flakes. Cook until tomatoes start to burst (approx. 5-7 minutes). Remove the pan from the heat and set aside.
Cut baguette down the center and into 4 equal pieces. Spray or brush with olive oil. Heat a griddle over medium-high heat. Place the olive oil side down on the pan and cook until toasted. Remove from the heat.
To assemble, spread an equal amount of pesto on each slice of bread, followed by the tomatoes, a handful of arugula, basil, balsamic vinegar and more black pepper.
Serve warm or at room temperature.