Lay tofu between paper towels to dry. Heat 1/4 cup oil in a large frying pan over medium-high heat until shimmering.
Spread cornstarch on a rimmed baking sheet and furikake on another. Stack tofu and cut into 1/2-in. cubes. Lightly toss tofu in cornstarch, then quickly but thoroughly roll and press in furikake. Fry in 2 batches until well-browned and crunchy, about 20 minutes total, and drain on paper towels.
Slice celery, dice apple, and cut radishes into thin wedges. In a big salad bowl, whisk remaining 1 1/2 tbsp. oil with chili garlic sauce and vinegar. Add celery, apple, radishes, spinach, salt, and tofu and toss to coat.
*Find in grocery stores' Asian-foods aisle.
Note: Nutritional analysis is per serving.