Place the sliced red onion in a large bowl and set a metal colander on top.
Add the tomatoes to the colander and sprinkle with a teaspoon salt. Gently toss to combine and set aside for 20-30 minutes.
Meanwhile, combine the onion powder, garlic powder, Italian seasoning, sea salt, and black pepper in a small bowl and stir to combine. Set aside.
Heat one tablespoon olive oil in a large skillet over medium heat. Arrange the bread slices in the skillet and drizzle the remaining olive oil on top. After this, sprinkle with the garlic and onion powder mixture and heat until the bread is nicely toasted on the bottom, approximately 4-5 minutes.
Turn the bread and sprinkle additional seasoning mixture on top. Continue heating until the bite-size pieces of bread until evenly browned, approximately 4-5 minutes. Remove from heat and tear the bread into bite-sized pieces. Place the torn bread chunks in a bowl and set aside.
Remove the colander from the large bowl and carefully drain out the tomato juice in the bowl to use in the vinaigrette. Set aside.