Heat a stove top grill pan or outdoor grill over medium-high heat.

Arrange the bread slices in a single layer on a baking sheet or plate. Drizzle with 1 tablespoon olive olive. Place the bread on the hot grill and cook for about 1 to 2 minutes on the first side, or until grill marks form. Flip over and continue to cook the second side for another minute. Return to baking sheet or plate and while hot, rub each bread slice with a garlic clove or two, as if you're grating the clove into the bread. Set aside.

Arrange the watermelon slices on the hot grill, and cook for about 2 to 3 minutes. Flip over and continue to cook for another minute or two. Transfer to a cutting board and allow to cool down completely.

In a large bowl, combine the shrimp with 1 tablespoon olive oil, 1 tablespoon red wine vinegar, 1/2 teaspoon salt, 1/2 teaspoon black pepper, crushed red pepper flakes, and 1 teaspoon oregano until evenly combined. Arrange the shrimp on the hot grill, in an even layer. Cook for about 5 to 7 minutes in total, turning the shrimp halfway. They should be pink and slightly charred around the edges. Transfer to a plate and allow to cool down.

Cut the rind off the cooled watermelon wedges and then cut into a medium dice. Transfer to a large mixing bowl. Add the red onion, cucumber, artichoke hearts, olives, feta, mint, chopped garlic and remaining 2 tablespoons oregano. Carefully toss everything together until just combined. You don't want to stir too much because the watermelon will breakdown. Add the remaining 2 tablespoons olive oil, 2 tablespoons red wine vinegar, lemon juice and season with a bit of salt and pepper to taste. Stir once more.

Serve chilled or at room temperature with a the grilled shrimp on top. Enjoy!