Place strawberries, sugar and lemon juice in a medium saucepan. Heat over medium-high and bring to a boil. Reduce heat to simmer and cook until strawberries have softened about 5-8 minutes. Remove from heat. Transfer strawberries to a blender and puree until smooth. Strain the mixture. Cool.
Whisk together the pureed strawberries with balsamic vinegar. Slowly add olive oil, whisking constantly. Season with salt and pepper. Set aside.
Combine seasoning for chicken including paprika, oregano, cayenne, cumin, salt, pepper, and onion powder. Liberally sprinkle seasoning mixture onto both sides of the chicken.
Heat oil in a saute pan over medium-high heat. Add chicken and sear on both sides, about 1 minute on each side. Transfer to a baking sheet. Finish cooking chicken in the oven until juices run clear, about 10-14 minutes. Remove from heat and let cool for 10 minutes before slicing.
Toss together spinach with feta, sliced strawberries, cranberries, toasted pecans, and salad dressing. Portion on four plates and top with sliced chicken. Serve.
Notes
The salad dressing can be prepared up to 5 days in advance.