Prepare rice according to package instructions.
Heat an ungreased pan over medium heat. Add the cumin, coriander, fennel and mustard and toast lightly, stirring to avoid burning. Remove spices from pan and let cool.
Grind the spices in a spice grinder or small food processor.
To make the dressing: In a small mixing bowl, blend the toasted spices well with the olive oil, lemon juice, salt and black pepper.
Using the same ungreased pan as the spices, lightly toast the pumpkin and sunflower seeds and remove from the pan.
Again, using the same ungreased pan, cook the Halloumi slices until browned. Flip and brown the other side. Remove the pan from heat and let the cheese cool slightly.
Cut the Halloumi slices into 1/2-inch pieces.
In a large mixing bowl, toss the rice with the spinach, toasted seeds, cheese, bell pepper and dressing. Serve.