Ras El Hanout-Spiced Salmon Skewers with Date-Studded Spinach

Combine 1 tablespoon oil and 1/4 teaspoon salt in a medium bowl. Add tomatoes and onion, toss to coat, then transfer to another bowl. In the empty bowl, combine 1 tablespoon oil, ras el hanout and 1/4 teaspoon salt. Add salmon and toss to coat. Thread a piece of salmon onto a 10-inch metal skewer, followed by a tomato and an onion piece. Repeat again, then finish with a third piece of salmon. Repeat with 7 more skewers. 

Preheat grill or heat a grill pan over medium-high heat. Oil the grill (or grill pan) by holding an oil-dipped paper towel with tongs. Grill the skewers, flipping to sear all sides, until the salmon is just cooked through and the tomatoes begin to soften, about 6 minutes total. 

Meanwhile, heat the remaining 3 tablespoons oil in a large skillet over medium heat. Add dates and garlic; cook, stirring, until the garlic is fragrant and softened and the dates caramelize a bit, 2 to 3 minutes. Increase heat to medium-high and, working in batches, add spinach; cook, stirring frequently, until wilted and silky, 3 to 4 minutes. Stir in lemon zest, lemon juice and the remaining 1/2 teaspoon salt. 

Serve the skewers with the spinach.