Combine the brown jasmine rice, 1½ cups water, and a pinch of salt in a small saucepan over high heat. Bring to a boil, cover, and reduce heat to low. Simmer until the rice is tender and all of the water is absorbed, about 30 to 35 minutes.
Halve the red onion and finely chop just half. Peel and mince 2 tsp ginger. Peel and mince 2 cloves garlic. Rinse and sort the petite golden lentils. Place a large skillet over medium heat with 1 tbsp vegetable oil. Once hot, add the chopped onion, minced ginger, and minced garlic. Cook, stirring frequently, until fragrant, about 2 to 4 minutes.
Add the Indian spice blend to the skillet, stir to combine, and cook for about 30 seconds. Add the petite golden lentils and 3 cups water. Bring to a boil, reduce heat to low, cover, and simmer the spiced dal until tender, about 18 to 20 minutes.
Thinly slice the remaining half onion. Using a peeler, peel the cucumber into long ribbons. Halve the lime. Zest the lime and add to a large bowl. Add the juice from the lime and the turbinado sugar and stir to combine. Add the sliced red onion, cucumber ribbons, and a pinch of salt, and toss the shaved cucumber salad until well coated.
Place the cashews in a small skillet over medium heat. Cook, tossing occasionally, until fragrant and lightly browned, about 4 to 6 minutes. Fluff the cooked jasmine rice with a fork. Season the spiced dal with 1 tsp salt.
To serve, divide the brown jasmine rice between large shallow bowls and top with the spiced dal. Top with the shaved cucumber salad and sprinkle with toasted cashews.