Preheat oven to 400 degrees. Mix together pecans, panko, salt, cayenne and black pepper.
Melt butter and oil in ovenproof skillet over medium-high heat. Dredge chicken in pecan-panko mixture. Sauté in skillet until brown on bottom, about 2 minutes. Turn chicken over and place skillet in oven. Bake 15-18 minutes until cooked through. Set aside; slice when cool.
Lower oven temperature to 350 degrees. Arrange tomatoes on baking sheet and toss with olive oil. Bake 30 minutes. Remove from oven and season with salt and pepper. Set aside.
To assemble, divide greens between two plates. Arrange red onion, cucumber, roasted tomatoes and chicken over greens. Top with blue cheese, if desired. Serve with ranch dressing or balsamic vinaigrette dressing.