1) Heat olive oil in a skillet; add onion and cook until softened. Add tomatoes and thyme, continue to cook and stir until tender, about 3 minutes more. Season with salt and pepper.
2) In the meantime, prepare the avocado smash by using an avocado masher tool to mash up the half avocado. Add a dash of lime juice and a pinch of salt and mix.
3) Toast the bread in a toaster oven. Let it cool.
4) Spread the smashed avocado on the bread. Top with the tomatoes, onions and thyme. Sprinkle with Kosher salt and freshly cracked black pepper to taste. Drizzle extra olive oil on top if desired.