Roasted Spiced Shrimp on Wilted Spinach

Name: Roasted Spiced Shrimp on Wilted Spinach
Ingredients: 6 large shrimp; 1/8 teaspoon chili powder; 1/8 teaspoon salt; 1/2 pound spinach (about 1 bunch); 2 scallions; 1 teaspoon fresh lime juice; 2 tablespoons water; 1 teaspoon grated peeled fresh gingerroot; 1/2 teaspoon sesame oil; Accompaniment: lime wedges