1. Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Add onion, salt, and garlic; sauté 3 minutes. Stir in okra.
2. Snip tomatoes in can until coarsely chopped using kitchen shears. Add tomatoes, their juice, and thyme to okra mixture. Bring to a boil; reduce heat, and simmer, uncovered, 35 minutes or until okra is tender, stirring occasionally.
3. Remove pan from heat; stir in vinegar and pepper. Sprinkle with parsley, if desired.