Preheat the oven to 400 degrees F.
Combine the cumin, coriander, and fennel seeds with a mortar and pestle, or slightly crush the whole seeds in a spice grinder, pulsing just until coriander is just broken; do not over process. (The spices can also be crushed using a heavy cast iron skillet.) Transfer the seeds to a small bowl, and toss with the salt and pepper.
Dip side of the salmon into the spice mixture to coat heavily. Repeat with all of the salmon cubes.
Heat a large ovenproof skillet over medium heat. Do not add any oil. Place the salmon cubes, spice side down, into the pan. Cook until the spices are dry, golden, and toasted, about 4 minutes. Immediately transfer the pan to the oven; remove when salmon is just cooked through, about 30 seconds. Transfer the salmon bites to a serving platter, and skewer with toothpicks. Serve warm Citrus Dipping Sauce.
Citrus Dipping Sauce:
2 tablespoons fresh lime juice
1 tablespoon fresh lemon juice
1/4 cup fresh orange juice
1 lime, 1 lemon, and 1 orange, zested
1/2 cup kaffir or sheep's-milk yogurt
1/2 cup plain yogurt
In a small saucepan over high heat, combine the lime, lemon, and orange juices with 1/2 teaspoon of the orange zest. Boil to reduce until thick and syrupy, making about 1 tablespoon. Remove from heat, and let cool.
In a medium bowl, combine the citrus syrup and the yogurts. Mix with a spoon until well combined. Season with salt, to taste. Keep refrigerated until ready to use. Sprinkle the remaining zest over the top before serving.
Yield: 1 cup