Empty rice into a fine mesh sieve and rinse under cold water. Add rice to a pot with 1 ½ cup (3 cups for 4 servings) salted water. Bring to a boil and reduce heat to low. Cover with a lid and cook for 18-20 minutes, or until grains are tender.
Prepare Mustard Glaze
Wash lemon and cut in half. In a small bowl, mix together grainy mustard, maple syrup, and apple cider vinegar. Season to taste with sambal oelek and lemon juice.
Wash and trim ends of green beans. Drain and pat dry steelhead with paper towel. Season both sides of fish with salt and pepper.
Cook Green Beans
Bring 1.5 litres (3 litres for 4 servings) salted water to a boil in a second pot. When water boils, add green beans. Cook for 2-3 minutes or until tender and bright green. Drain with a fine mesh sieve and return green beans to po. Season with ½ tbsp. (1 tbsp. for 4 servings) olive oil, and salt and pepper to taste. Cover with a lid to keep warm.
When rice from Step 1 is almost ready, heat 1 tbsp. (2 tbsp. for 4 servings) olive oil in a medium skillet over medium-high. Add steelhead to skillet and cook for 2-3 minutes on one side. Turn over and cook other side for 2 minutes. Remove fish from skillet and drain excess oil into a metal bowl. Place skillet over low heat. Put fish back in skillet and add mustard glaze while swirling skillet. Cook for 1 minute, until glaze thickens and begins to coat fish. Turn off heat and turn fish to coat.
Divide rice onto plates with green beans. Add fish next to green beans. Spoon any extra glaze on top. Squeeze lemon over fish if desired. Enjoy!