Calamari with asian spinach

For the spinach:
2 tablespoons olive oil
1 medium red onion, finely diced
3 cloves garlic, minced
3 medium tomatoes, diced
2 tablespoons dark soy sauce
1 teaspoon grated fresh ginger
6 drops hot sauce
1 pound frozen spinach, thawed
1-1/2 pounds cleaned calamari (about 24 pieces)
Juice of 1 lemon
1/2 teaspoon salt
1/2 teaspoon freshly ground black pepper
2 tablespoons sesame oil

1. To make the spinach: In a large skillet, heat olive oil. Add onion and garlic; saute 4 minutes. Add tomatoes, soy sauce, ginger, and hot sauce; simmer 5 minutes. Add spinach; bring to a boil. Remove from heat and keep warm.
2. In a dish or resealable plastic bag, place calamari, lemon juice, salt, and pepper. Toss to coat calamari. Marinate 10 minutes.
3. Thread six 12-inch skewers with calamari. Brush with sesame oil. Place skewers in center of cooking grate. Grill 4 minutes, turning once halfway through grilling time. Serve skewers on warm Asian spinach.