Preheat oven to 325°.
To prepare flan, combine first 3 ingredients in a bowl, and stir with a whisk. Stir in crabmeat, green onions, 1/4 teaspoon salt, and pepper. Divide the mixture evenly among 4 (6-ounce) custard cups or ramekins coated with cooking spray. Place cups on a baking sheet. Bake at 325° for 50 minutes or until a knife inserted in center comes out clean. Remove cups from baking sheet. Loosen the edges of custards with a knife or rubber spatula. Place a small plate, upside down, on top of each cup; invert onto plates. Keep warm.
To prepare soup, heat oil in a Dutch oven over medium heat. Add chopped onion and garlic; sauté 5 minutes. Stir in broth, 2 cups peas, and 1/4 teaspoon salt. Bring to a boil; reduce heat, and simmer 20 minutes or until peas are tender. Cool slightly. Place the soup and spinach in a blender, and process until smooth. Set aside and keep warm. Add 1/2 cup peas to pan, and cook, covered, 4 minutes or until just tender.
Place 1/2 cup chopped tomato into each of 4 soup bowls. Arrange 1 flan on top of the tomato, and ladle 1 cup soup around each flan. Top each serving with 2 tablespoons steamed peas.