Make Simple Vinaigrette – combine all ingredients and whisk thoroughly. Set aside to allow the flavors to mingle.
Heat a grill pan coated with cooking spray over medium high heat. Coat the bread slices with olive oil cooking spray then place into the grill pan and cook until toasted on both sides for 5 minutes. Remove and cube into bite sized pieces.
Add the olive oil to the grill pan then place the mushrooms into the pan. Let them sit, leaving them alone, for 3-4 minutes then flip them over for another 2 minutes, or until golden. Pour into a large bowl. Add the asparagus and onion to the grill pan, adding cooking spray if needed. Cook, stirring often for 3-4 minutes, or until fork tender; pour into the bowl with the mushrooms. Add the zucchini chunks and tomato quarters to the grill pan. Cook for 3-4 minutes on each side or until tender. Gently place them into the bowl. Add the cubed bread pieces to the bowl.
Season the veggies and bread with sea salt and freshly cracked pepper to taste then toss to coat. Drizzle some of the vinaigrette on top then toss to coat evenly. Taste & re-season or add more vinaigrette if needed. Serve immediately. Enjoy.