Lemony Scallop Salad

Name: Lemony Scallop Salad
Ingredients: 1½ pounds sea scallops; 8 cups packaged, precut mixed salad greens; 1 medium tomato, cut into wedges; 1 lemon, cut into wedges; 1 cup lemon juice; 2 cloves garlic, minced; ½ teaspoon dried oregano; ¼ teaspoon freshly ground black pepper; 1 medium red onion, thinly sliced into rings