1. For the Salad: Toss the spinach and watercress together in a large bowl; set aside.

2. Toast the almonds in a 12-inch skillet over medium heat, shaking the pan occasionally, until fragrant and lightly browned, about 3 minutes; transfer them to the bowl with the greens. Wipe out the skillet using a wad of paper towels.

3.For the Scallops: Place the scallops on a paper towel-lined plate or baking sheet; season the scallops with salt and pepper. Lay a single layer of paper towels over the scallops; set aside.

4. Add 2 tablespoons of the vegetable oil to the empty skillet and return to high heat until just smoking. Meanwhile, press the paper towel flush to the scallops to dry. Add half of the scallops, dry-side facing down, and cook until evenly golden, 1 to 2 minutes. Using tongs, transfer the scallops, browned side facing up, to a large plate; set aside. Wipe out the skillet using a wad of paper towels. Repeat with the remaining 2 tablespoons oil and the remaining scallops. Once the first side is golden, turn the heat to medium, turn the scallops over with tongs, and return the first batch of scallops to the pan, golden side facing up. Cook until the sides on all the scallops have firmed up and all but the middle third of each scallop is opaque, 30 to 60 seconds longer. Transfer all the scallops to a large plate; set aside.

5. For the Dressing: Wipe the skillet clean with a wad of paper towels. Add the olive oil, onion, thyme, and 1/2 teaspoon salt to the skillet and return to medium-high heat; cook until the onions are slightly softened, about 1 minute. Add the oranges and vinegar to the pan and swirl to incorporate. Remove from the heat.

6. To Finish the Salad: Pour the warm dressing over the salad mixture and gently toss to wilt. Divide the spinach salad among four plates and arrange the scallops on top. Serve immediately.